Water Quality Standards To Protect Aquatic Life in the Delaware River, 88315-88336 [2023-27758]
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of Management and Budget under
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October 4, 1993) and 13563 (88 FR
21879, April 11, 2023);
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because they approve a state program;
• Are not significant regulatory
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• Are not subject to requirements of
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application of those requirements would
be inconsistent with the CAA.
In addition, the SIP is not approved
to apply on any Indian reservation land
or in any other area where EPA or an
Indian tribe has demonstrated that a
tribe has jurisdiction. In those areas of
Indian country, the proposed rule does
not have tribal implications and will not
impose substantial direct costs on tribal
governments or preempt tribal law as
specified by Executive Order 13175 (65
FR 67249, November 9, 2000).
Executive Order 12898 (Federal
Actions To Address Environmental
Justice in Minority Populations and
Low-Income Populations, 59 FR 7629,
Feb. 16, 1994) directs Federal agencies
to identify and address
‘‘disproportionately high and adverse
human health or environmental effects’’
of their actions on minority populations
and low-income populations to the
greatest extent practicable and
permitted by law. EPA defines
environmental justice (EJ) as ‘‘the fair
treatment and meaningful involvement
of all people regardless of race, color,
national origin, or income with respect
to the development, implementation,
and enforcement of environmental laws,
regulations, and policies.’’ EPA further
defines the term fair treatment to mean
that ‘‘no group of people should bear a
disproportionate burden of
environmental harms and risks,
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including those resulting from the
negative environmental consequences of
industrial, governmental, and
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policies.’’
EPD did not evaluate EJ
considerations as part of its SIP
submittals; the CAA and applicable
implementing regulations neither
prohibit nor require such an evaluation.
EPA did not perform an EJ analysis and
did not consider EJ in these proposed
actions. Due to the nature of the actions
being proposed here, these proposed
actions are expected to have a neutral to
positive impact on the air quality of the
affected area. Consideration of EJ is not
required as part of these proposed
actions, and there is no information in
the record inconsistent with the stated
goal of E.O. 12898 of achieving EJ for
people of color, low-income
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List of Subjects in 40 CFR Part 52
Environmental protection, Air
pollution control, Carbon monoxide,
Incorporation by reference, Nitrogen
dioxide, Ozone, Particulate matter,
Reporting and recordkeeping
requirements, Sulfur oxides, Volatile
organic compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: December 14, 2023.
Jeaneanne Gettle,
Acting Regional Administrator, Region 4.
[FR Doc. 2023–28105 Filed 12–20–23; 8:45 am]
BILLING CODE 6560–50–P
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 131
[EPA–HQ–OW–2023–0222; FRL 10760–01–
OW]
RIN 2040–AG30
Water Quality Standards To Protect
Aquatic Life in the Delaware River
Environmental Protection
Agency (EPA).
ACTION: Proposed rule.
AGENCY:
On December 1, 2022, the
U.S. Environmental Protection Agency
(EPA) determined that revised water
quality standards are necessary to
protect aquatic life in certain water
quality management zones of the
Delaware River. Specifically, the EPA
issued an Administrator’s
Determination, pursuant to the Clean
Water Act (CWA), finding that a revised
designated use to protect aquatic life
propagation and corresponding
dissolved oxygen criteria to protect that
SUMMARY:
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use are necessary in Zone 3, Zone 4, and
the upper portion of Zone 5 (in total,
river miles 108.4 to 70.0) of the
Delaware River. The CWA requires the
EPA to publish proposed water quality
standards following an Administrator’s
Determination. Thus, the EPA is
proposing to promulgate an aquatic life
designated use that includes
propagation and protective water
quality criteria for dissolved oxygen for
Zone 3, Zone 4, and upper Zone 5 of the
Delaware River.
DATES: Comments must be received on
or before February 20, 2024. Public
hearing: the EPA will hold two public
hearings during the public comment
period. Please refer to the
SUPPLEMENTARY INFORMATION section for
additional information on the public
hearings.
ADDRESSES: You may send comments,
identified by Docket ID No. EPA–HQ–
OW–2023–0222, by any of the following
methods:
• Federal eRulemaking Portal:
https://www.regulations.gov/ (our
preferred method). Follow the online
instructions for submitting comments.
• Mail: U.S. Environmental
Protection Agency, EPA Docket Center,
Office of Water Docket, Mail Code
28221T, 1200 Pennsylvania Avenue
NW, Washington, DC 20460.
• Hand Delivery or Courier: EPA
Docket Center, WJC West Building,
Room 3334, 1301 Constitution Avenue
NW, Washington, DC 20004. The Docket
Center’s hours of operations are 8:30
a.m.–4:30 p.m., Monday through Friday
(except Federal holidays).
Instructions: All submissions received
must include the Docket ID No. for this
rulemaking. Comments received may be
posted without change to https://
www.regulations.gov/, including any
personal information provided. For
detailed instructions on sending
comments and additional information
on the rulemaking process, see the
‘‘Public Participation’’ heading of the
SUPPLEMENTARY INFORMATION section of
this document.
FOR FURTHER INFORMATION CONTACT:
Hannah Lesch, Office of Water,
Standards and Health Protection
Division (4305T), Environmental
Protection Agency, 1200 Pennsylvania
Avenue NW, Washington, DC 20460;
telephone number: (202) 566–1224;
email address: Lesch.Hannah@epa.gov.
SUPPLEMENTARY INFORMATION: This
proposed rule preamble is organized as
follows:
I. Public Participation
A. Written Comments
B. Participation in Public Hearings
II. General Information
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A. Does this action apply to me?
III. Background
A. Statutory and Regulatory Authority
B. Relevant Ecological History of the
Delaware River
C. Administration of Water Quality
Standards in the Delaware River
D. Currently Applicable Aquatic Life
Designated Uses and Dissolved Oxygen
Criteria
E. Summary of the EPA’s Administrator’s
Determination
IV. Proposed Water Quality Standards
A. Scope of EPA’s Proposed Rule
B. Proposed Aquatic Life Designated Use
C. Dissolved Oxygen Criteria To Protect
Aquatic Life Propagation
V. Endangered Species Act Consultation
VI. Applicability
VII. Conditions Where Federal Water Quality
Standards Would Not Be Promulgated or
Would Be Withdrawn
A. Conditions Where Federal Standards
Would Not Be Promulgated
B. Conditions Where Federal Standards
Would Be Withdrawn
VIII. Alternative Regulatory Approaches and
Implementation Mechanisms
A. Water Quality Standards Variances
B. NPDES Permit Compliance Schedules
C. Clean Water Act Section 303(d)/305(b)
Water Quality Assessments
IX. Economic Analysis
X. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory
Planning and Review and Executive
Order 14094: Modernizing Regulatory
Review
B. Paperwork Reduction Act (PRA)
C. Regulatory Flexibility Act (RFA)
D. Unfunded Mandates Reform Act
(UMRA)
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
G. Executive Order 13045: Protection of
Children From Environmental Health
and Safety Risks
H. Executive Order 13211: Actions That
Significantly Affect Energy Supply,
Distribution, or Use
I. National Technology Transfer and
Advancement Act (NTTAA)
J. Executive Order 12898: Federal Actions
To Address Environmental Justice in
Minority Populations and Low-Income
Populations and Executive Order 14096:
Revitalizing Our Nation’s Commitment
to Environmental Justice for All
I. Public Participation
A. Written Comments
Submit your comments, identified by
Docket ID No. EPA–HQ–OW–2023–
0222, at https://www.regulations.gov
(the EPA’s preferred method), or the
other methods identified in the
ADDRESSES section. Once submitted,
comments cannot be edited or removed
from the docket. The EPA may publish
any comment received to its public
docket. Do not submit to the EPA’s
docket at https://www.regulations.gov
any information you consider to be
Confidential Business Information (CBI),
Proprietary Business Information (PBI),
or other information whose disclosure is
restricted by statute. Multimedia
submissions (audio, video, etc.) must be
accompanied by a written comment.
The written comment is considered the
official comment and should include
discussion of all points you wish to
make. The EPA will generally not
consider comments or comment
contents located outside of the primary
submission (i.e., on the web, cloud, or
other file sharing system). Please visit
https://www.epa.gov/dockets/
commenting-epa-dockets for additional
submission methods; the full EPA
public comment policy; information
about CBI, PBI, or multimedia
submissions; and general guidance on
making effective comments.
B. Participation in Public Hearings
The EPA is offering two public
hearings so that interested parties may
also provide oral comments on this
proposed rulemaking. For more details
on the public hearings and to register to
attend the hearings, please visit https://
www.epa.gov/wqs-tech/water-qualitystandards-delaware-river.
II. General Information
A. Does this action apply to me?
A range of individuals and entities
could be affected by this rulemaking, if
finalized. For example, entities that
discharge pollutants to certain waters
under the jurisdiction of the states of
Delaware, New Jersey, and
Pennsylvania—such as industrial
facilities and municipalities that
manage stormwater, separate sanitary,
or combined sewer systems—could be
indirectly affected by this rulemaking
because Federal water quality standards
(WQS) promulgated by the EPA would
be the applicable WQS for these waters
for CWA purposes (Table 1 of this
preamble). Specifically, these WQS
would be the applicable standards that
must be used in CWA regulatory
programs, such as permitting under the
National Pollutant Discharge
Elimination System (NPDES) under
CWA section 402 1 and identifying
impaired waters under CWA section
303(d). In addition, individuals and
entities who rely on or benefit from
aquatic life in those waters may be
indirectly affected.
TABLE 1—ENTITIES POTENTIALLY AFFECTED BY THIS PROPOSED RULE
Category
Examples of potentially affected entities
Industry ................................................................
Industrial point sources discharging to certain waters in Delaware, New Jersey, and Pennsylvania. Commercial fishing operations that harvest fish.
Publicly owned treatment works or similar facilities responsible for managing stormwater, separate sanitary, or combined sewer systems that discharge to certain waters in Delaware,
New Jersey, and Pennsylvania.
Anglers and tourists seeking recreational opportunities related to aquatic life in certain waters
in Delaware, New Jersey, and Pennsylvania.
Municipalities, including those with stormwater
or combined sewer system outfalls.
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Recreation and Tourism ......................................
This table is not intended to be
exhaustive, but rather provides a guide
for readers regarding entities that could
be indirectly affected by this action. If
you have questions regarding the
applicability of this action to a
particular entity, consult the person
1 Before any water quality-based effluent limit
would be included in an NPDES permit, the
permitting authority (here, the states of Delaware,
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listed in the FOR FURTHER INFORMATION
section above.
CONTACT
III. Background
A. Statutory and Regulatory Authority
CWA section 101(a)(2) establishes a
national goal of ‘‘water quality which
New Jersey, and Pennsylvania), must first
determine whether a discharge ‘‘will cause or has
the reasonable potential to cause, or contribute to
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provides for the protection and
propagation of fish, shellfish, and
wildlife, and provides for recreation in
and on the water’’ (hereafter,
collectively referred to as ‘‘101(a)(2)
uses’’ or ‘‘101(a)(2) goals’’), wherever
attainable. The EPA’s regulation at 40
CFR 131.10(g) implements this statutory
an excursion above any WQS.’’ 40 CFR
122.44(d)(1)(i) and (ii).
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provision by requiring that WQS protect
101(a)(2) uses unless those uses are
shown to be unattainable.
Under the CWA, states have the
primary responsibility for reviewing,
establishing, and revising WQS
applicable to their waters (CWA section
303(c)). WQS define the desired
condition of a water body, in part, by
designating the use or uses to be made
of the water and by setting the numeric
or narrative water quality criteria to
protect those uses (40 CFR 131.2,
131.10, and 131.11). There are two
primary categories of water quality
criteria: human health criteria and
aquatic life criteria. Human health
criteria protect designated uses such as
public water supply, recreation, and fish
and shellfish consumption. Aquatic life
criteria protect designated uses such as
protection and propagation of fish,
invertebrates, and other aquatic species.
Regardless of their category, water
quality criteria ‘‘must be based on sound
scientific rationale and must contain
sufficient parameters or constituents to
protect the designated use. For waters
with multiple use designations, the
criteria shall support the most sensitive
use’’ (40 CFR 131.11(a)(1)).
States are required to hold a public
hearing to review applicable WQS at
least once every three years and, if
appropriate, revise or adopt new
standards (CWA section 303(c)(1); 40
CFR 131.20(a)). Every three years, states
must also reexamine water body
segments that do not include the
101(a)(2) uses to determine if new
information has become available that
indicates the 101(a)(2) uses are
attainable, and if so, revise the WQS
accordingly (40 CFR 131.20(a)). Any
new or revised WQS must be submitted
to the EPA for review and approval or
disapproval (CWA section 303(c)(2)(A)
and (c)(3)).
CWA section 303(c)(4)(B)
independently authorizes the
Administrator to determine that a new
or revised standard is necessary to meet
CWA requirements; this action is
frequently referred to as an
‘‘Administrator’s Determination.’’
Pursuant to CWA section 303(c)(4)(B),
after making an Administrator’s
Determination, the EPA must propose
and promulgate WQS specified in the
Administrator’s Determination. If a state
adopts and the EPA approves WQS that
address the Administrator’s
Determination prior to the EPA’s
promulgation, then the EPA would no
longer be required to promulgate WQS.
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B. Relevant Ecological History of the
Delaware River
The Delaware River has historically
been home to numerous species of
ecological, recreational, and economic
importance; however, centuries of
anthropogenic water quality impacts
and habitat degradation, peaking in the
mid-twentieth century, made portions of
the river unsuitable for many aquatic
species. In the 1700s and 1800s, many
native fish species in the Delaware River
faced declining populations due to
overharvesting and the installation of
physical barriers that prevented fish
passage.2 Further population declines of
native oxygen-sensitive species—such
as the Atlantic Sturgeon (Acipenser
oxyrinchus oxyrinchus), American Shad
(Alosa sapidissima), Shortnose Sturgeon
(Acipenser brevirostrum), and Striped
Bass (Morone saxatilis), among
others 3—were linked to accelerating
degradation of water quality through the
first half of the 1900s, including
seasonal anoxia (i.e., absence of oxygen)
by the mid-twentieth century in Zone 3,
Zone 4, and the upper portion of Zone
5 of the Delaware River.4
Dissolved oxygen is an important
water quality parameter that can
significantly influence the distribution
and abundance of aquatic organisms
and ecological relationships in aquatic
ecosystems. Aquatic organisms need to
obtain adequate levels of dissolved
oxygen to maintain and support normal
functioning, including during sensitive
2 Hardy, C.A. (1999). Fish or Foul: A History of
the Delaware River Basin Through the Perspective
of the American Shad, 1682 to the Present.
Pennsylvania History, 66(4), 506–534. https://
digitalcommons.wcupa.edu/hist_facpub/13; Secor,
D.H. and Waldman, J. (1999). Historical abundance
of Delaware Bay Atlantic sturgeon and potential
rate of recovery. American Fisheries Society
Symposium. 23. 203–216. https://
www.researchgate.net/publication/291783957_
Historical_abundance_of_Delaware_Bay_Atlantic_
sturgeon_and_potential_rate_of_recovery; Smith,
T.I.J., & Clugston, J.P. (1997) Status and
management of Atlantic sturgeon, Acipenser
oxyrinchus, in North America. Environmental
Biology of Fishes 48, 335–346. https://doi.org/
10.1023/A:1007307507468; National Marine
Fisheries Service. (1998). Recovery Plan for the
Shortnose Sturgeon (Acipenser brevirostrum).
Prepared by the Shortnose Sturgeon Recovery Team
for the National Marine Fisheries Service, Silver
Spring, Maryland. 104 pages. https://repository.
library.noaa.gov/view/noaa/15971.
3 Stoklosa, A.M., Keller, D.H., Marano, R., and
Horwitz, R.J. (2018). ‘‘A Review of Dissolved
Oxygen Requirements for Key Sensitive Species in
the Delaware Estuary.’’ Academy of Natural
Sciences of Drexel University. November 2018.
https://www.nj.gov/drbc/library/documents/
Review_DOreq_KeySensSpecies_DelEstuary_
ANStoDRBCnov2018.pdf.
4 See citations in footnote 2 of this preamble;
Atlantic States Marine Fisheries Commission.
(1981). Interstate Fisheries Management Plan for the
Striped Bass. https://www.asmfc.org/uploads/file/
1981FMP.pdf.
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life stages, such as spawning, larval
development, and juvenile growth.5 As
dissolved oxygen levels decrease in a
waterbody, the rate at which aquatic
organisms can obtain oxygen from the
water decreases, resulting in impaired
growth and reduced survival.
Maintaining a healthy ecosystem
requires dissolved oxygen levels above
thresholds that impair growth and
survival of aquatic species.
1. Causes of Low Dissolved Oxygen in
the Specified Zones of the Delaware
River
Discharges of untreated or poorly
treated municipal and industrial
wastewater into the specified zones of
the Delaware River have historically
been a major cause of water quality
degradation, including oxygen
depletion.6 While conditions have
significantly improved, inputs of
oxygen-consuming wastes from
wastewater dischargers, especially
ammonia (NH3) and ammonium (NH4+)
(which in combination are hereafter
referred to as ‘‘ammonia nitrogen’’), as
well as sediment-water ammonium flux
and sediment oxygen demand continue
to be significant sources of oxygen
demand in the specified zones of the
Delaware River.7
Along the Delaware River, untreated
wastewater discharges typically occur
during and after rainfall due to
combined sewer overflows (CSOs),
which are a source of nutrients (i.e.,
nitrogen and phosphorus), sediments,
and toxic contaminants, and can lead to
increased chemical and biological
oxygen demand in the river.8 Although
the cumulative impact of historical
5 United States Environmental Protection Agency.
(2021). Factsheet on Water Quality Parameters:
Dissolved Oxygen. July 2021. Document ID: EPA
841F21007B. https://www.epa.gov/system/files/
documents/2021-07/parameter-factsheet_do.pdf;
United States Environmental Protection Agency.
(2023a). Indicators: Dissolved Oxygen. June 9, 2023.
https://www.epa.gov/national-aquatic-resourcesurveys/indicators-dissolved-oxygen.
6 Hardy (1999); Delaware River Basin
Commission. (2022a). Analysis of Attainability:
Improving Dissolved Oxygen and Aquatic Life Uses
in the Delaware River Estuary. September 2022
Draft. See section 3—‘‘Factors that can Improve
Dissolved Oxygen in the Fish Maintenance Area.’’
https://www.nj.gov/drbc/library/documents/
AnalysisAttainability/AnalysisAttainability_
DRAFTsept2022.pdf.
7 Delaware River Basin Commission. (2022b).
Modeling Eutrophication Processes in the Delaware
River Estuary—Three-Dimensional Water Quality
Model. https://www.nj.gov/drbc/library/documents/
AnalysisAttainability/WQModelCalibrationRpt_
DRAFTsept2022.pdf.
8 Miskewitz, R. and Uchrin, C. (2013). In-Stream
Dissolved Oxygen Impacts and Sediment Oxygen
Demand Resulting from Combined Sewer Overflow
Discharges. Journal of Environmental Engineering,
139(10). https://doi.org/10.1061/(ASCE)EE.19437870.0000739.
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CSOs on sediment oxygen demand in
the Delaware River has not been
estimated, CSOs can over time increase
or maintain sediment oxygen demand as
untreated organic material settles on the
riverbed and is broken down by oxygen
consuming bacteria (thus, removing
oxygen from the water column), a
process that continues long after the end
of an overflow event.9 CSOs have been
a persistent source of pollutants in the
specified zones of the Delaware River
for over a century. For example, sewer
overflows from Philadelphia in the early
1900s deposited over 200,000 tons of
solids per year, which, in combination
with other solid wastes, created deposits
12 feet deep in the river.10 From July 1,
2021, to June 30, 2022, Philadelphia’s
wastewater system alone discharged
over 1.7 billion cubic feet of CSOs into
the Delaware River.11
Although most point source
discharges today are treated, treated
effluent can still contain high levels of
ammonia nitrogen, which depletes
oxygen in the water as bacteria oxidize
ammonia into nitrite, nitrate and
dinitrogen gas.12 During the reporting
periods from July through October 2022,
major wastewater treatment facilities
along the Delaware River discharged
ammonia nitrogen at monthly average
concentrations ranging from a low of
0.07 milligrams nitrogen per liter (mgN/L) at the Florence Township Sewage
Treatment Plant in New Jersey
(discharging into Zone 2 of the Delaware
River) to a high of 35 mg-N/L at the
Camden County Municipal Utilities
Authority in New Jersey (discharging
into Zone 3 of the Delaware River).13
2. Endangered Species in the Specified
Zones of the Delaware River
The Delaware River is home to two
oxygen-sensitive fish species—
Shortnose Sturgeon and Atlantic
Sturgeon—that are protected under the
Federal Endangered Species Act (ESA).
9 Miskewitz
and Uchrin (2013).
(1999).
11 Philadelphia Water Department. (2022).
Combined Sewer Management Program Annual
Report. Stormwater Management Program Annual
Report. See Appendix D—‘‘NPDES Annual CSO
Status Report FY 2022,’’ Table 2—‘‘Overflow
Summary for 7/1/2021–6/30/2022.’’ https://water.
phila.gov/pool/files/fy22-npdes-annual-report.pdf.
12 United States Environmental Protection
Agency. (2023b). Ammonia. https://www.epa.gov/
caddis-vol2/ammonia.
13 Each individual reporting period is one month
long. For the reporting period ending on September
30, 2022, Florence Township Municipal Building
discharged an average of .07 mg/L of ammonia. For
the reporting period ending on July 31, 2022,
Camden County Municipal Utilities Authority
discharged an average of 35 mg/L of ammonia.
Source: U.S. Environmental Protection Agency.
Integrated Compliance Information System (ICIS).
Database. Retrieved June 29, 2023.
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10 Hardy
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All populations of Shortnose Sturgeon
were listed as endangered in 1967.14
Across the U.S., Shortnose Sturgeon
face ongoing threats due to water
pollution, habitat degradation, and
fisheries bycatch, among other factors.15
While the historic population size of
Shortnose Sturgeon in the Delaware
River remains unknown, in 2006 the
population was estimated to be
approximately 12,000 adults.16 The
New York Bight distinct population
segment (DPS) of Atlantic Sturgeon—
which includes the population found in
the Delaware River—was listed as
endangered under the ESA in 2012.17 In
2017, the National Oceanic and
Atmospheric Administration (NOAA
Fisheries) designated the Delaware
River, among others, as critical habitat
for the New York Bight DPS of Atlantic
Sturgeon,18 and reaffirmed its
endangered listing in 2022 following a
five-year review of its status.19 The
remnant population of the New York
Bight DPS of Atlantic Sturgeon faces
ongoing threats due to water quality in
natal rivers, such as the Delaware River,
as well as climate change, ship strikes,
fisheries bycatch, habitat loss, and
entanglement in fishing gear.20 21 Like
the Shortnose Sturgeon, the historic
14 Federal Register, Vol. 32, No. 48 (32 FR 4000).
March 11, 1967. https://www.fisheries.noaa.gov/
s3//2022-12/4000-4002.pdf.
15 NOAA Fisheries. (2023a). Shortnose
Sturgeon—Overview. https://www.fisheries.
noaa.gov/species/shortnose-sturgeon.
16 Id.; NOAA Fisheries. (2023b). Shortnose
Sturgeon—Populations. https://www.fisheries.
noaa.gov/species/shortnose-sturgeon#populations.
17 Federal Register, Vol. 77, No. 24. February 6,
2012. 77 FR 5879. https://www.federalregister.gov/
documents/2012/02/06/2012-1946/endangeredand-threatened-wildlife-and-plants-threatened-andendangered-status-for-distinct.
18 Federal Register, Vol. 82, No. 158 (82 FR
39160). August 17, 2017. 50 CFR part 226. https://
www.federalregister.gov/documents/2017/08/17/
2017-17207/endangered-and-threatened-speciesdesignation-of-critical-habitat-for-the-endangerednew-york-bight.
19 National Marine Fisheries Service. (2022). New
York Bight Distinct Population Segment of Atlantic
Sturgeon (Acipenser oxyrinchus oxyrinchus), 5-Year
Review: Summary and Evaluation. February 17,
2022. https://www.fisheries.noaa.gov/resource/
document/new-york-bight-distinct-populationsegment-atlantic-sturgeon-5-year-review.
20 Ibid. See Section 2.3.2, ‘‘Five-Factor Analysis
(threats, conservation measures, and regulatory
mechanisms)’’, A. through E., pp. 14–25.
21 Dunton, K.J., Jordaan, A., Conover, D.O.,
McKown, K.A., Bonacci, L.A., and Frisk, M.G.
(2015). Marine Distribution and Habitat Use of
Atlantic Sturgeon in New York Lead to Fisheries
Interactions and Bycatch. Marine and Coastal
Fisheries 7:18–32. https://doi.org/10.1080/
19425120.2014.986348; Atlantic Sturgeon Bycatch
Working Group. (2022). Action Plan to Reduce
Atlantic Sturgeon Bycatch in Federal Large Mesh
Gillnet Fisheries. NOAA National Marine Fisheries
Service. https://media.fisheries.noaa.gov/2022-09/
Final-Action-Plan-to-Reduce-Atlantic-SturgeonBycatch.pdf.
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population size of Atlantic Sturgeon is
not well documented. However, in
1890, when the population was already
declining, there were approximately
180,000 female Atlantic Sturgeon in the
Delaware River.22 Despite
improvements in dissolved oxygen
levels since the 1970s, it is estimated
that only 125–250 adult Atlantic
Sturgeon currently return to spawn in
the Delaware River.23
In addition to being listed as
endangered under the ESA, available
evidence suggests that Shortnose
Sturgeon and Atlantic Sturgeon are the
most oxygen-sensitive species in the
specified zones of the Delaware River.
In general, all sturgeon species share
common life history traits,24 among
which they are recognized to be
relatively more sensitive to low
dissolved oxygen levels compared to
other co-occurring fish.25 26 Sturgeons
are considered unusually sensitive to
hypoxia given their documented
metabolic and behavioral responses and
limited ability to oxyregulate.27 Juvenile
Atlantic Sturgeon are particularly
sensitive to low dissolved oxygen levels,
especially at high water temperatures,28
such as those typically present at the
peak of summer in the Delaware River.29
A literature review across oxygen22 Secor
and Waldman (1999).
S.L., Sard, N.M., Brundage, H.M.,
Johnson, R.L., Lubinski, B.A., Eackles, M.S., Park,
I.A., Fox, D.A., and Kazyak, D.C. (2022). Evaluating
Sources of Bias in Pedigree-Based Estimates of
Breeding Population Size. Ecological Applications
32(5): e2602. https://doi.org/10.1002/eap.2602.
24 Federal Register, Vol. 82, No. 158 (82 FR
39161). August 17, 2017. 50 CFR part 226. pp.
39161–39163. https://www.federalregister.gov/
documents/2017/08/17/2017-17207/endangeredand-threatened-species-designation-of-criticalhabitat-for-the-endangered-new-york-bight.
25 Ibid. p. 39162, see Dees (1961), Sulak and
Clugston (1999), Billard and Lecointre (2001), Secor
and Niklitschek (2002), and Pikitch et al. (2005),
cited therein.
26 Stoklosa et al. (2018) ; Secor, D.H. and
Niklitschek, E.J. (2001). Hypoxia and Sturgeons:
Report to the Chesapeake Bay Program Dissolved
Oxygen Criteria Team. March 29, 2001.Reference
Number: [UMCES] CBL 01–0080. https://
www.researchgate.net/publication/277065759_
Hypoxia_and_Sturgeons_report_to_the_
Chesapeake_Bay_Program_Dissolved_Oxygen_
Criteria_Team.
27 Secor and Niklitschek (2001). Oxyregulation
refers to an organism’s ability to maintain metabolic
rates as the oxygen level in the water declines.
28 Secor, D., and T. Gunderson. (1998). Effects of
hypoxia and temperature on survival, growth, and
respiration of juvenile Atlantic sturgeon, Acipenser
oxyrinchus. Fishery Bulletin 96:603–613.;
Niklitschek, E. (2001). Bioenergetics modeling and
assessment of suitable habitat for juvenile Atlantic
and shortnose sturgeons (Acipenser oxyrinchus and
A. brevirostrum) in the Chesapeake Bay. University
of Maryland at College Park.
29 More information is available in the associated
document, Technical Support Document for the
Proposed Rule: Water Quality Standards to Protect
Aquatic Life in the Delaware River.
23 White,
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sensitive species in the Delaware River
indicates that Atlantic Sturgeon,
particularly the juvenile life stage, have
the highest documented dissolved
oxygen requirements for growth and
survival when compared to other
oxygen-sensitive species in the specified
zones of the Delaware River.30 In its
five-year review of the listing of the
New York Bight DPS of Atlantic
Sturgeon, NOAA Fisheries observed a
continuation of low dissolved oxygen
conditions in the Delaware River around
the expected location of age 0–1
Atlantic Sturgeon.31 Low oxygen levels
can lead to habitat displacement effects
whereby juvenile Atlantic Sturgeon
seeking relief are constrained to waters
that remain suboptimal for growth due
to other limiting factors (e.g., higher
salinity waters).32 NOAA Fisheries also
noted studies linking age 0–1 Atlantic
Sturgeon capture rates in the fall to the
preceding summer dissolved oxygen
conditions in the Delaware River,
providing further evidence that low
dissolved oxygen levels are a
contributor to the mortality of juvenile
Atlantic Sturgeon.33
3. Dissolved Oxygen Trends in the
Specified Zones of the Delaware River
Dissolved oxygen levels in Zone 3,
Zone 4, and the upper portion of Zone
5 of the Delaware River mirror trends in
historic pollutant loading and recent
pollution control efforts in the river.
Average summer dissolved oxygen
levels in the Delaware River near
Chester, Pennsylvania (Zone 4) declined
from near saturation in the late 1880s to
near zero (i.e., anoxia) in the 1950s and
1960s.34 Starting in 1970, dissolved
oxygen levels began to increase steadily
in association with declining ammonia
nitrogen concentrations in the river.35
Reductions in nutrient concentrations,
including ammonia nitrogen, have been
documented across the Delaware River
watershed through at least 2018.36
However, dissolved oxygen levels in the
summer remain low enough to limit the
growth and survival of oxygen-sensitive
30 Stoklosa
et al. (2018).
Marine Fisheries Service (2022). See
Section 2.3.2.1, ‘‘Present or threatened destruction,
modification, or curtailment of its habitat or range.’’
32 Ibid. See Allen et al. (2014), cited therein.
33 Ibid. See Moberg and DeLucia (2016), Stetzar et
al. (2015), and Park (2020), cited therein.
34 Sharp, J. (2010). Estuarine oxygen dynamics:
What can we learn about hypoxia from long-time
records in the Delaware estuary? Limnology and
Oceanography, 55(2), 535–548.
35 Sharp (2010).
36 Shoda, M.E., and Murphy, J.C. (2022). Waterquality trends in the Delaware River Basin
calculated using multisource data and two methods
for trend periods ending in 2018. U.S. Geological
Survey Scientific Investigations Report 2022–5097.
https://doi.org/10.3133/sir20225097.
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species and life stages, such as juvenile
Atlantic Sturgeon.37 Recent modeling
studies have shown that further
reductions in pollutant loading,
including a reduction in the volume and
frequency of CSOs as well as enhanced
treatment of ammonia nitrogen
discharges, could significantly improve
the dissolved oxygen conditions in the
relevant zones of the Delaware River.38
C. Administration of Water Quality
Standards in the Delaware River
In 1961, the Delaware River Basin
Compact established the Delaware River
Basin Commission (DRBC), comprised
of the states of Delaware, New Jersey,
New York,39 and Pennsylvania and the
Federal Government, to jointly manage
the Delaware River Basin’s water
resources.40 Through DRBC, each state
participates in the shared governance of
this regional resource and maintains
sovereign rights over the portion of the
river within its jurisdiction.41
Pursuant to the Delaware River Basin
Compact, DRBC adopts WQS for
interstate waters, including the
Delaware River Estuary.42 However as
noted above, under the CWA, states
have the primary responsibility for
reviewing, establishing, and revising
WQS applicable to their waters, and
must submit new or revised WQS to the
37 More information is available in the associated
document, Technical Support Document for the
Proposed Rule: Water Quality Standards to Protect
Aquatic Life in the Delaware River; Delaware River
Basin Commission (2022a); Niklitschek, E., and D.
Secor. (2009a). Dissolved oxygen, temperature and
salinity effects on the ecophysiology and survival
of juvenile Atlantic sturgeon in estuarine waters: I.
Laboratory results. Journal of Experimental Marine
Biology and Ecology 381:S150–S160. https://
doi.org/10.1016/j.jembe.2009.07.018; Stoklosa et al.
(2018).
38 Delaware River Basin Commission (2022a,
2022b).
39 Although portions of the Delaware River
Estuary are within New York’s jurisdiction, the
EPA’s proposed rulemaking is not applicable to
waters under New York’s jurisdiction (see section
IV.A. of this preamble: Scope of EPA’s Proposed
Rule). Therefore, the EPA does not discuss New
York’s WQS further in this proposed rulemaking.
40 DRBC was established pursuant to Federal law
(75 Stat. 688 (1961)).
41 Delaware River Basin Compact, art. 1, ‘‘Short
Title, Definitions, Purpose and Limitations,’’
§ 1.3(a), (b), & (c) ‘‘Purpose and Findings,’’ pp. 3 &
4, and art. 5, ‘‘Pollution Control,’’ § 5.5(b), ‘‘Further
Jurisdiction,’’ p. 11, (1961), available at https://
www.nj.gov/drbc/library/documents/compact.pdf.
42 Delaware River Basin Compact, art. 5,
‘‘Pollution Control,’’ § 5.2, ‘‘Policy and Standards,’’
p. 11 (1961), available at https://www.nj.gov/drbc/
library/documents/compact.pdf (DRBC ‘‘may adopt
and from time to time amend and repeal rules,
regulations and standards to control . . . future
pollution and abate existing pollution’’). DRBC, the
states, and the EPA refer to these rules, regulations,
and standards as equivalent to WQS under the
CWA. As such, the term WQS is used herein to refer
to these rules, regulations, and standards.
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EPA for review and approval or
disapproval.
Given the unique interjurisdictional
management of the Delaware River
Estuary, WQS are submitted to the EPA
for review through a process
coordinated across the state, regional,
and Federal levels. This process begins
when DRBC adopts WQS for the
Delaware River Estuary. To comply with
CWA section 303(c), the Estuary states
of Delaware, New Jersey, and
Pennsylvania have provisions in their
state WQS regulations that explicitly
reference or implicitly incorporate
DRBC’s WQS as the applicable WQS for
the portions of the river under their
jurisdictions. When DRBC adopts new
or revised WQS, each relevant member
state submits a certification to the EPA
from that state’s attorney general or
other appropriate legal authority, in
accordance with 40 CFR 131.6(e). Those
certifications provide that DRBC’s new
or revised WQS were duly adopted
pursuant to state law. The EPA then
reviews whether those WQS are
consistent with the CWA and the EPA’s
implementing regulation and approves
or disapproves them.
D. Currently Applicable Aquatic Life
Designated Uses and Dissolved Oxygen
Criteria
In 1967, DRBC adopted WQS for the
zones of the Delaware River included in
this proposed rule.43 Based on the
conditions of the Delaware River at the
time, DRBC concluded that
‘‘propagation of fish’’ was not attainable
for Zone 3, Zone 4, and the upper
portion of Zone 5 (in total, river miles
108.4 to 70.0) of the Delaware River
(hereafter, referred to as ‘‘specified
zones’’ or ‘‘relevant zones’’),44 due to
the presence of industrial and
municipal discharges and associated
low dissolved oxygen levels. DRBC,
therefore, adopted WQS to include
‘‘maintenance of resident fish and other
aquatic life,’’ ‘‘passage of anadromous
fish,’’ and a dissolved oxygen criterion
of 3.5 mg/L, as a daily average, for these
43 Delaware River Basin Commission. (2013).
Delaware River Basin Water Code. https://
www.nj.gov/drbc/library/documents/watercode.pdf.
44 A map showing the Delaware River watershed
and the specified zones is available in the docket
(Docket ID No. EPA–HQ–OW–2023–0222) as well
as in each of the support documents associated with
this rule: Technical Support Document for the
Proposed Rule: Water Quality Standards to Protect
Aquatic Life in the Delaware River; Economic
Analysis for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware
River; and Environmental Justice Analysis for the
Proposed Rule: Water Quality Standards to Protect
Aquatic Life in the Delaware River.
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zones of the Delaware River.45 46
Because these WQS provide for the
‘‘maintenance’’ and ‘‘passage’’ of aquatic
life (i.e., ‘‘protection’’) but not the
‘‘propagation of fish, shellfish and
wildlife,’’ these WQS are not consistent
with the goals specified in CWA section
101(a)(2). However, these WQS adopted
in 1967 remain applicable for Zone 3,
Zone 4, and the upper portion of Zone
5 of the Delaware River as directly
referred to or implicitly incorporated in
Delaware’s, New Jersey’s, and
Pennsylvania’s WQS.
1. Delaware’s, New Jersey’s, and
Pennsylvania’s Current Aquatic Life
Designated Uses
As described in section III.C. of this
preamble, Delaware, New Jersey, and
Pennsylvania each has its own WQS for
the specified zones of the Delaware
River under its jurisdiction. Delaware’s
current aquatic life designated use for
the specified zones of the Delaware
River includes all life stages, thus
including the propagation component of
the CWA section 101(a)(2) use. New
Jersey’s aquatic life designated use for
the specified zones of the Delaware
River incorporate by reference the
designated uses in DRBC’s Water
Quality Regulations. Pennsylvania’s
aquatic life designated uses for the
specified zones of the Delaware River
align with DRBC’s ‘‘maintenance’’ and
‘‘passage’’ designated use (Table 2 of
this preamble). Therefore, neither New
Jersey’s nor Pennsylvania’s aquatic life
designated use for the specified zones of
the Delaware River include the
propagation component of the CWA
section 101(a)(2) use.
TABLE 2—CURRENT AQUATIC LIFE DESIGNATED USES IN ZONE 3, ZONE 4, AND UPPER-ZONE 5 OF THE DELAWARE RIVER
Entity
Designated use
DRBC 1 ....................
Delaware 2 ...............
New Jersey 4 ...........
Maintenance of resident fish and other aquatic life, passage of anadromous fish, wildlife.
Fish, Aquatic Life & Wildlife.3
The designated uses for the mainstem Delaware River and Delaware Bay are those contained in the DRBC Water Quality
Regulations.
Warm Water Fishes (Maintenance Only); Migratory fishes (Passage Only).6
Pennsylvania 5 ........
1 Delaware River Basin Commission. ‘‘Administrative Manual—Part III Water Quality Regulations with Amendments Through December 7,
2022.’’ Accessed May 3, 2023. https://www.nj.gov/drbc/library/documents/WQregs.pdf.
2 Delaware Administrative Code. ‘‘7401 Surface Water Quality Standards.’’ Title 7 Natural Resources & Environmental Control. Delaware Department of Natural Resource and Environmental Control. Accessed May 3, 2023. https://regulations.delaware.gov/AdminCode/title7/7000/7400/
7401.pdf.
3 Delaware defines Fish, Aquatic Life & Wildlife as, ‘‘all animal and plant life found in Delaware, either indigenous or migratory, regardless of
life stage or economic importance.’’ A footnote specifies that this use includes shellfish propagation.
4 New Jersey Administrative Code. ‘‘N. J. A. C. 7:9B Surface Water Quality Standards.’’ Accessed May 3, 2023. https://dep.nj.gov/wp-content/
uploads/rules/rules/njac7_9b.pdf.
5 Pennsylvania Code. ‘‘Chapter 93. Water Quality Standards.’’ Commonwealth of Pennsylvania. Accessed May 3, 2023. https://
www.pacodeandbulletin.gov/secure/pacode/data/025/chapter93/025_0093.pdf.
6 Pennsylvania defines its ‘‘Warm Water Fishes’’ designated use as, ‘‘Maintenance and propagation of fish species and additional flora and
fauna which are indigenous to a warm water habitat’’ and defines its ‘‘Migratory Fishes’’ designated use as, ‘‘Passage, maintenance and propagation of anadromous and catadromous fishes and other fishes which move to or from flowing waters to complete their life cycle in other
waters.’’ For the specified zones of the Delaware River, Pennsylvania excluded propagation from the designated uses by specifying ‘‘Maintenance Only’’ and ‘‘Passage Only’’ in parentheses.
2. Delaware’s, New Jersey’s, and
Pennsylvania’s Current Dissolved
Oxygen Criteria
For dissolved oxygen in the relevant
zones, all three states incorporate
DRBC’s water quality criteria by
reference; therefore, DRBC’s dissolved
oxygen criteria are the applicable
criteria for the relevant zones in each
state (Table 3 of this preamble). As
explained above with respect to the
aquatic life designated use, DRBC’s
dissolved oxygen criteria for the
specified zones of the Delaware River do
not protect for aquatic life propagation
and are therefore not consistent with
CWA section 101(a)(2) goals.
TABLE 3—CURRENT DISSOLVED OXYGEN CRITERIA IN ZONE 3, ZONE 4, AND UPPER-ZONE 5 OF THE DELAWARE RIVER
Entity
Dissolved oxygen aquatic life criteria
DRBC 1 ....................
24-hour average concentration shall not be less than 3.5 mg/l. During the periods from April 1 to June 15, and September
16 to December 31, the dissolved oxygen shall not have a seasonal average less than 6.5 mg/l in the entire zone.
For waters of the Delaware River and Delaware Bay, duly adopted Delaware River Basin Commission (DRBC) Water
Quality Regulations shall be the applicable criteria.
For parameters with criteria in the DRBC Water Quality Regulations, the criteria contained therein are the applicable criteria.
See DRBC Water Quality Regulations.
Delaware 2 ...............
New Jersey 3 ...........
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Pennsylvania 4 ........
1 Delaware River Basin Commission. ‘‘Administrative Manual—Part III Water Quality Regulations with Amendments Through December 7,
2022.’’ Accessed May 3, 2023. https://www.nj.gov/drbc/library/documents/WQregs.pdf.
2 Delaware Administrative Code. ‘‘7401 Surface Water Quality Standards.’’ Title 7 Natural Resources & Environmental Control. Delaware Department of Natural Resource and Environmental Control. Accessed May 3, 2023. https://regulations.delaware.gov/AdminCode/title7/7000/7400/
7401.pdf.
3 New Jersey Administrative Code. ‘‘N. J. A. C. 7:9B Surface Water Quality Standards.’’ Accessed May 3, 2023. https://dep.nj.gov/wp-content/
uploads/rules/rules/njac7_9b.pdf.
4 Pennsylvania Code. ‘‘Chapter 93. Water Quality Standards.’’ Commonwealth of Pennsylvania. Accessed May 3, 2023. https://
www.pacodeandbulletin.gov/secure/pacode/data/025/chapter93/025_0093.pdf.
45 Delaware River Basin Commission. (2015).
‘‘Existing Use Evaluation for Zones 3, 4, & 5 of the
Delaware Estuary Based on Spawning and Rearing
of Resident and Anadromous Fishes.’’ September
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30, 2015. https://www.state.nj.us/drbc/library/
documents/ExistingUseRpt_zones3-5_sept2015.pdf.
46 Anadromous fish are species that are born and
reared as juveniles in freshwater, migrate to marine
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and return to their natal, freshwater rivers to spawn.
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3. Intersection of Delaware’s, New
Jersey’s, and Pennsylvania’s Current
Aquatic Life Designated Uses and
Dissolved Oxygen Criteria With CWA
101(a)(2) Goals
Table 4 of this preamble provides a
summary outlining whether Delaware’s,
New Jersey’s, and Pennsylvania’s
current aquatic life designated uses
align with CWA section 101(a)(2) goals
and whether each state’s current
dissolved oxygen criteria are protective
of an aquatic life designated use that
includes propagation. As explained
above, Delaware is the only state that
includes aquatic life propagation in its
designated uses for the specified zones
of the Delaware River. However, none of
the three states’ dissolved oxygen water
quality criteria for the specified zones
88321
are protective of fish and shellfish
propagation. Therefore, none of the
states, and by extension none of the
specified zones of the Delaware River,
currently has a set of WQS for aquatic
life that are fully consistent with the
CWA section 101(a)(2) goals (i.e., ‘‘water
quality which provides for the
protection and propagation of fish,
shellfish, and wildlife [. . .]’’).
TABLE 4—INTERSECTION OF DELAWARE’S, NEW JERSEY’S, AND PENNSYLVANIA’S CURRENT AQUATIC LIFE DESIGNATED
USES AND DISSOLVED OXYGEN CRITERIA WITH CWA 101(a)(2) GOALS
State
Applicable zone(s)
Designated use includes CWA
section 101(a)(2) propagation
component
Delaware ........................................
New Jersey ....................................
Pennsylvania ..................................
Upper-5 .........................................
3, 4, Upper-5 ................................
3, 4 ................................................
Yes ................................................
No .................................................
No .................................................
E. Summary of the EPA’s
Administrator’s Determination
On December 1, 2022, the EPA
determined that the CWA section
101(a)(2) use of propagation is now
attainable and therefore revised WQS
are necessary to protect aquatic life in
certain water quality management zones
of the Delaware River.47 Specifically,
the EPA issued an Administrator’s
Determination, pursuant to CWA
section 303(c)(4)(B), finding that a
revised designated use to protect aquatic
life propagation and corresponding
dissolved oxygen criteria to protect that
use are necessary in Zone 3, Zone 4, and
the upper portion of Zone 5 (in total,
river miles 108.4 to 70.0) of the
Delaware River. The Administrator’s
Determination can be accessed at
https://www.epa.gov/wqs-tech/federallypromulgated-water-quality-standardsspecific-states-territories-and-tribes.
Dissolved oxygen criteria
protective of aquatic life
propagation
No.
No.
No.
IV. Proposed Water Quality Standards
A. Scope of EPA’s Proposed Rule
In accordance with the
Administrator’s Determination, the
EPA’s proposed rule, if finalized, would
apply to Zone 3, Zone 4, and the upper
portion of Zone 5 of the Delaware River
(in total, river miles 108.4 to 70.0), for
the states of Delaware, New Jersey, and
Pennsylvania (Table 5 of this preamble).
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TABLE 5—ZONES OF THE DELAWARE RIVER COVERED BY THE EPA’S PROPOSED RULE
Segment of the Delaware River
River miles
Zone 3 ...............................................................
Zone 4 ...............................................................
Zone 5—Upper Portion .....................................
108.4 to 95.0 ....................................................
95.0 to 78.8 ......................................................
78.8 to 70.0 ......................................................
New Jersey, Pennsylvania.
New Jersey, Pennsylvania.
Delaware, New Jersey.
B. Proposed Aquatic Life Designated
Use
The EPA is proposing to promulgate
a revised aquatic life designated use for
the specified zones of the Delaware
River to meet the CWA section 101(a)(2)
goals (i.e., ‘‘water quality which
provides for the protection and
propagation of fish, shellfish, and
wildlife’’), as specified in the EPA’s
Administrator’s Determination.48
Although the relevant zones of the
Delaware River are each under the
jurisdiction of two or more states (Table
5 of this preamble), CWA section 303(c)
assigns the individual states the role of
adopting WQS. Therefore, the EPA is
evaluating the aquatic life uses on a
state-by-state basis.
As explained in section III.D. of this
preamble, Delaware’s ‘‘Fish, Aquatic
Life & Wildlife’’ designated use includes
all life stages of indigenous and
migratory organisms; therefore,
Delaware’s aquatic life designated use in
the specified zones under its
jurisdiction is already consistent with
the CWA section 101(a)(2) goals and no
revisions to Delaware’s aquatic life
designated use are necessary to meet
CWA requirements. In contrast, New
Jersey’s and Pennsylvania’s aquatic life
designated uses for the relevant zones of
the Delaware River under their
jurisdiction do not include
‘‘propagation’’ and are therefore not
consistent with CWA section 101(a)(2)
goals. As explained in section III.E. of
this preamble, the EPA determined that
propagation is now an attainable use in
the specified zones of the Delaware
River.49 Therefore, for the portions of
the specified zones under New Jersey’s
and Pennsylvania’s jurisdiction, a
47 December 1, 2022. Letter from Radhika Fox,
Assistant Administrator, EPA Office of Water, to
Steven J. Tambini, Executive Director, Delaware
River Basin Commission; Shawn M. Garvin,
Secretary, Delaware Department of Natural
Resources and Environmental Control; Shawn M.
LaTourette, Commissioner, New Jersey Department
of Environmental Protection; and Ramez Ziadeh,
Acting Secretary, Pennsylvania Department of
Environmental Protection.
48 The EPA’s Administrator’s Determination
stated, ‘‘EPA is determining [. . . that] revised
aquatic life designated uses that provide for
propagation of fish, consistent with CWA section
101(a)(2) and 40 CFR 131.20(a) [. . .] are necessary
for zone 3, zone 4, and the upper portion of zone
5 (in total, river miles 108.4 to 70.0) of the Delaware
River Estuary, to meet the requirements of the
CWA.’’
49 December 1, 2022. Letter from Radhika Fox,
Assistant Administrator, EPA Office of Water, to
Steven J. Tambini, Executive Director, Delaware
River Basin Commission; Shawn M. Garvin,
Secretary, Delaware Department of Natural
Resources and Environmental Control; Shawn M.
LaTourette, Commissioner, New Jersey Department
of Environmental Protection; and Ramez Ziadeh,
Acting Secretary, Pennsylvania Department of
Environmental Protection.
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revised aquatic life designated use that
includes propagation is necessary to
meet CWA requirements and ensure that
the specified zones of the Delaware
River are consistent with CWA section
101(a)(2) goals.
Thus, the EPA is proposing to
promulgate an aquatic life designated
use for Zone 3, Zone 4, and the upper
portion of Zone 5 of the Delaware River
(in total, river miles 108.4 to 70.0) for
the states of New Jersey and
Pennsylvania, as follows: Protection and
propagation of resident and migratory
aquatic life.
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C. Dissolved Oxygen Criteria To Protect
Aquatic Life Propagation
The EPA is proposing to establish
dissolved oxygen criteria—derived from
the latest sound scientific information—
for Delaware, New Jersey, and
Pennsylvania, for the specified zones of
the Delaware River. The proposed
dissolved oxygen criteria would protect
the EPA’s proposed designated use for
New Jersey and Pennsylvania, as well as
Delaware’s current aquatic life
designated use for the specified zones.
1. Derivation of Dissolved Oxygen
Criteria
To derive protective dissolved oxygen
criteria for the specified zones of the
Delaware River, the EPA used methods
adapted from peer-reviewed literature
and data from laboratory studies
relevant to oxygen-sensitive sturgeon
species in the Delaware River. Although
the methods and data are from peerreviewed scientific literature, the EPA is
nonetheless in the process of
completing an external peer review on
the application of these methods and
data in this context where the EPA is
proposing criteria to protect proposed
and applicable aquatic life designated
uses that include propagation. This
section presents a summary of the data
and methods that the EPA used to
derive protective dissolved oxygen
criteria for this proposed rulemaking.
First, the EPA describes the Agency’s
existing dissolved oxygen national
recommendations and guidance
documents. Then, the EPA explains
how the Agency selected three seasons
to derive criteria protective of oxygensensitive species in the relevant zones of
the Delaware River. Next, the EPA
details an Atlantic Sturgeon cohort
model used to derive criteria protective
of juvenile Atlantic Sturgeon during the
season associated with their growth and
development. After that, the EPA
explains how criteria were developed to
protect oxygen-sensitive species during
the other two seasons. Lastly, the EPA
concludes with an explanation for
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proposing criteria expressed as percent
oxygen saturation, rather than as
concentration. This section is intended
to be a high-level summary of the EPA’s
criteria derivation methods and results
for this proposed rulemaking. More
details and information are available in
the associated technical support
document, Technical Support
Document for the Proposed Rule: Water
Quality Standards to Protect Aquatic
Life in the Delaware River. The EPA will
consider information received during
the public comment period (detailed
above), in addition to the external peer
review of the technical support
document, and accordingly may make
changes to the proposed criteria for a
final rule.
Existing the EPA Methodology and
Guidance Documents
Under CWA section 304(a), the EPA
publishes, from time to time, national
recommended aquatic life criteria for a
variety of pollutants and parameters.
The EPA’s national recommended
criteria for dissolved oxygen in
freshwater and saltwater environments
are from the 1986 Quality Criteria for
Water (‘‘Gold Book’’) 50 and the 2000
Ambient Aquatic Life Water Quality
Criteria for Dissolved Oxygen
(Saltwater): Cape Cod to Cape Hatteras
(‘‘Virginian Province Document’’),51
respectively. The EPA’s
recommendations in the Virginian
Province Document state that, ‘‘in cases
where a threatened or endangered
species occurs at a site, and sufficient
data exist to suggest that it is more
sensitive at concentrations above the
criteria, it is appropriate to consider
development of site-specific criteria
based on this species.’’ 52 As explained
previously in section III.B. of this
preamble, Atlantic Sturgeon and
Shortnose Sturgeon are federally listed
as endangered under the ESA and are
uniquely sensitive to hypoxia. Given the
availability of laboratory data specific to
the oxygen requirements of Atlantic
Sturgeon and Shortnose Sturgeon, the
EPA chose to derive site-specific criteria
to protect the oxygen-sensitive
endangered species in the specified
50 United States Environmental Protection
Agency. (1986). Quality Criteria for Water 1986.
Document ID: EPA 440/5–86–001. May 1, 1986.
https://www.epa.gov/sites/default/files/2018-10/
documents/quality-criteria-water-1986.pdf.
51 United States Environmental Protection
Agency. (2000). Ambient Aquatic Life Water
Quality Criteria for Dissolved Oxygen (Saltwater):
Cape Cod to Cape Hatteras. Document ID: EPA–
822–R–00–012. November 2000. https://
www.epa.gov/sites/default/files/2018-10/
documents/ambient-al-wqc-dissolved-oxygen-capecode.pdf.
52 Id. Page 41.
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zones of the Delaware River and not rely
on the national recommendations in the
Gold Book or Virginian Province
Document in this instance.
Delineating Seasons for Criteria
Derivation
In consideration of available
information, including information
developed by DRBC, the EPA is
proposing to delineate three distinct
seasons for dissolved oxygen criteria
development that are intended to
protect Atlantic Sturgeon early life
stages, while also protecting a range of
other aquatic species’ sensitive life
stages in the specified zones. The EPA
is proposing to define the Spawning and
Larval Development season as occurring
from March 1 to June 30, which
generally covers spawning and egg and
larval development periods for many
oxygen-sensitive species, including
Atlantic Sturgeon, Shortnose Sturgeon,
American Shad, Atlantic Rock Crab,
Channel Catfish, Striped Bass,
Largemouth Bass, White Perch, and
Yellow Perch.53 The EPA is proposing
to define the Juvenile Development
season as occurring from July 1 to
October 31 and the Overwintering
season as occurring from November 1 to
February 28/29, based on young-of-theyear juvenile Atlantic Sturgeon growth
rates.54 By November, growth rates are
reduced by low water temperatures
despite relatively high levels of
dissolved oxygen.55 While the EPA is
proposing to define seasons largely
based on the early life stages of Atlantic
Sturgeon, the proposed seasons also
generally correspond with early life
stages of other oxygen-sensitive species
in the specified zones of the Delaware
River. By developing criteria that are
protective of Atlantic Sturgeon, which,
as described in section III.B. of this
preamble, is the most oxygen-sensitive
species in the relevant zones of the
Delaware River, the EPA concluded that
the criteria would also be protective of
other less oxygen-sensitive resident and
53 Stoklosa et al. (2018); Delaware River Basin
Commission (2015); Moberg, T. and M. DeLucia.
(2016). Potential Impacts of Dissolved Oxygen,
Salinity and Flow on the Successful Recruitment of
Atlantic Sturgeon in the Delaware River. The
Nature Conservancy. Harrisburg, PA. https://
www.conservationgateway.org/Conservation
Practices/Freshwater/HabitatProtection
andRestoration/Documents/DelawareAtlantic
SturgeonReport_TNC5172016.pdf.
54 Moberg and DeLucia. (2016).
55 This conclusion was based on results of the
growth model, described in sections 3.3.3 and 4.1.2
of the associated document, Technical Support
Document for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware
River.
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migratory aquatic species in the
specified zones of the Delaware River.
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Ecological Modeling To Derive Criteria
for the Juvenile Development Season
The EPA obtained recent and highquality data from a variety of sources,
described below and detailed in the
associated technical support document,
to evaluate oxygen requirements of
Atlantic Sturgeon in each season. The
EPA quantified water quality conditions
in the specified zones of the Delaware
River using recent and high-quality
monitoring data from two locations in
the Delaware River. Since the Atlantic
Sturgeon was listed as an endangered
species in 2012, there have been few
recent studies documenting their
oxygen requirements. However,
available data on sturgeon growth and
mortality from Campbell and Goodman
(2004), Niklitschek and Secor (2009a),
and EPA (2003), along with methods
from Niklitschek and Secor (2005) and
Niklitschek and Secor (2009b), water
quality monitoring data, and juvenile
Atlantic Sturgeon abundance data from
the Delaware Department of Natural
Resources and Environmental Control
(DNREC) provided the EPA with
sufficient data to establish quantitative
relationships between age-0 juvenile
sturgeon growth, mortality, and habitat
suitability.56
56 Campbell, J., and L. Goodman. (2004). Acute
sensitivity of juvenile shortnose sturgeon to low
dissolved oxygen concentrations. Transactions of
the American Fisheries Society 133:722–776;
Niklitschek, E., and D. Secor. (2009a). Dissolved
oxygen, temperature and salinity effects on the
ecophysiology and survival of juvenile Atlantic
sturgeon in estuarine waters: I. Laboratory results.
Journal of Experimental Marine Biology and
Ecology 381:S150–S160. https://doi.org/10.1016/
j.jembe.2009.07.018; United States Environmental
Protection Agency. (2003). Ambient Water Quality
Criteria for Dissolved Oxygen, Water Clarity and
Chlorophyll a for the Chesapeake Bay and its Tidal
Tributaries. Document ID: EPA 903–R–03–002.
April 2003. https://nepis.epa.gov/Exe/ZyPDF.cgi/
P100YKPQ.PDF?Dockey=P100YKPQ.PDF;
Niklitschek, E.J., and D.H. Secor. (2005). Modeling
spatial and temporal variation of suitable nursery
habitats for Atlantic sturgeon in the Chesapeake
Bay. Estuarine, Coastal and Shelf Science 64:135–
148. https://doi.org/10.1016/j.ecss.2005.02.012;
Niklitschek, E.J., and D.H. Secor. (2009b). Dissolved
oxygen, temperature and salinity effects on the
ecophysiology and survival of juvenile Atlantic
sturgeon in estuarine waters: II. Model development
and testing. Journal of Experimental Marine Biology
and Ecology 381:S161–S172. https://doi.org/
10.1016/j.jembe.2009.07.019; USGS 01467200
Delaware River at Penn’s Landing, Philadelphia,
PA. Retrieved March 9, 2023. https://waterdata.
usgs.gov/nwis/inventory/?site_
no=01467200&agency_cd=USGS; USGS 01477050
Delaware River at Chester PA. Retrieved January 31,
2023. https://waterdata.usgs.gov/nwis/
inventory?agency_code=USGS&site_no=01477050;
Park, I. (2023). State of Delaware Annual
Compliance Report for Atlantic Sturgeon. Delaware
Division of Fish and Wildlife, Department of
Natural Resources and Environmental Control.
September 2023.
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The EPA followed the peer-reviewed
cohort modeling approach of
Niklitschek and Secor (2005) to evaluate
the effects of temperature, salinity, and
dissolved oxygen on the potential
growth and mortality of a hypothetical
cohort or group of juvenile Atlantic
Sturgeon spawned during a single
year.57 The cohort model uses growth
and mortality rates to calculate the
instantaneous daily production
potential, or the instantaneous amount
of biomass produced per unit of cohort
biomass per day. The EPA used the
cohort model to estimate the fraction of
the cohort that survives from July 1
through October 31 (i.e., the Juvenile
Development season) and the relative
change in biomass for the same period.
As part of the cohort model, the EPA
developed a new mortality model and
implemented a peer-reviewed
bioenergetics-based growth model
described by Niklitschek and Secor
(2009b) to predict the daily
instantaneous mortality rate and growth
rate, respectively, for members of the
cohort. To develop a mortality model,
the EPA fit a regression to experimental
data to predict mortality resulting from
low dissolved oxygen at any given
temperature and percent oxygen
saturation.58 Mortality rates of juvenile
sturgeons increased with declining
dissolved oxygen levels and increased at
higher rates with both declining
dissolved oxygen and increasing water
temperature. The EPA validated the
results of the mortality model by using
observed water quality data to predict
relative abundance of the Atlantic
Sturgeon young-of-year cohort on
October 31 and comparing those results
to catch data from DNREC’s juvenile
abundance surveys.59 The growth model
takes a bioenergetic approach that
accounts for temperature-controlled
maximum metabolic rates that may be
further limited by oxygen levels. Low
oxygen levels limit overall metabolic
rates and cause a shift in the allocation
of available energy away from growth.
Predicted growth rates reflect the
balance between energy inputs and
losses and are therefore reduced by low
57 Water temperature and salinity can affect the
oxygen requirements of aquatic species and are
needed to compute percent oxygen saturation, a
measure of dissolved oxygen availability to aquatic
organisms, from dissolved oxygen concentrations.
58 Experimental data are from Campbell and
Goodman 2004, Niklitschek and Secor 2009a.
59 USGS 01467200 Delaware River at Penn’s
Landing, Philadelphia, PA. Retrieved March 9,
2023. https://waterdata.usgs.gov/nwis/inventory/
?site_no=01467200&agency_cd=USGS; USGS
01477050 Delaware River at Chester, PA. Retrieved
January 31, 2023. https://waterdata.usgs.gov/nwis/
inventory?agency_code=USGS&site_no=01477050;
Park (2023).
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oxygen. Water quality monitoring data
in the relevant zones of the Delaware
River show that the lowest oxygen
levels coincided with the highest water
temperatures, resulting in lower growth
rates than either condition would cause
alone.
Habitat Suitability Indices have been
used in the context of fish-habitat
relationships, conservation
management, and habitat evaluation to
quantify the capacity of a given habitat
to support essential life functions (e.g.,
growth, survival, reproduction) of a
selected species.60 For this proposed
rulemaking, the EPA defined a Habitat
Suitability Index (HSI) for Atlantic
Sturgeon as the instantaneous daily
production potential, which was
calculated using the cohort model. HSI
evaluates the combined effect of percent
oxygen saturation, water temperature,
and salinity on the potential growth and
survival of juvenile Atlantic Sturgeon
during the Juvenile Development
season. The EPA used quantile
generalized additive models (QGAMs)
to quantify relationships between
computed values of HSI in each year
and corresponding seasonal percentiles
of daily dissolved oxygen for that year.61
QGAMs can model the non-linear
relationship between dissolved oxygen
and HSI as well as predict the expected
median HSI, rather than the expected
mean.
The EPA followed the approach of
Niklitschek and Secor (2005) to define
suitable habitat for juvenile Atlantic
Sturgeon growth and survival as
habitats with water quality resulting in
HSI greater than zero. When HSI is less
than or equal to zero, seasonal average
mortality rates are greater than or equal
to seasonal average growth rates and the
overall biomass of the cohort is likely to
decrease. Conversely, a cohort of
60 E.g., Woodland, R.J., Secor, D.H., and
Niklitschek, E.J. (2009). Past and Future Habitat
Suitability for the Hudson River Population of
Shortnose Sturgeon: A Bioenergetic Approach to
Modeling Habitat Suitability for an Endangered
Species. American Fisheries Society Symposium
69: 589–604; Collier, J.J., Chiotti, J.A., Boase, J.,
Mayer, C.M., Vandergoot, C.S., and Bossenbroek,
J.M. (2022). Assessing habitat for lake sturgeon
(Acipenser fulvescens) reintroduction to the
Maumee River, Ohio using habitat suitability index
models. Journal of Great Lakes Research. 48(1):
219–228. https://doi.org/10.1016/j.jglr.2021.11.006;
Brown, S.K., Buja, K.R., Jury, S.H., Monaco, M.E.,
and Banner, A. (2000). Habitat Suitability Index
Models for Eight Fish and Invertebrate Species in
Casco and Sheepscot Bays, Maine. North American
Journal of Fisheries Management, 20(2): 408–435,
https://doi.org/10.1577/1548-8675(2000)
020%3C0408:HSIMFE%3E2.3.CO;2.
61 A percentile (e.g., 10th percentile) is the
dissolved oxygen level below which the
corresponding fraction (e.g., 10%) of the daily
dissolved oxygen values during the season falls
below. In this case, the season is the Juvenile
Development season (July 1–October 31).
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juveniles utilizing habitat with HSI
greater than zero has the potential to
increase its biomass during the Juvenile
Development season, thus contributing
to successful propagation. Therefore, to
derive protective dissolved oxygen
criteria, the EPA evaluated seasonal
percentiles of percent oxygen saturation
to find the lowest value at which the
QGAMs predict expected median HSI>0
as the minimum thresholds for percent
oxygen saturation that, if attained,
would provide suitable habitat during
that seasonal period. The EPA requests
comment on the conclusion that HSI
greater than zero defines suitable habitat
for juvenile Atlantic Sturgeon growth
and survival, or alternatively, if
evidence could support that a value of
HSI less than zero could also be
protective or if a higher HSI threshold
may be needed to protect propagation in
the specified zones. Similarly, the EPA
requests comment on its use of QGAM
to relate percentiles of dissolved oxygen
levels to the conditional median HSI.
These models can be understood to find
the minimum dissolved oxygen level
that if achieved would result in an
expectation that HSI would be equal to
or greater than zero as often or more
often than if it is less than zero. As an
alternative, the QGAM could predict a
lower conditional percentile, providing
a high degree of certainty that HSI
would be greater than zero if the
dissolved oxygen level was attained. For
example, at the dissolved oxygen level
where the expected 25th percentile
HSI=0, HSI would be expected to equal
or exceed zero 75% of the time.
The predicted HSI value relies on an
expected distribution of percent oxygen
saturation values during the season;
therefore, the EPA selected two percent
oxygen saturation percentiles as
thresholds at or above which median
HSI is expected to be greater than zero
to maintain the expected distribution of
percent oxygen saturation values. These
two percentiles—the 10th percentile
and the 50th percentile—describe the
protective seasonal distribution of
dissolved oxygen values. When both the
10th percentile and 50th percentile are
attained, they function together to
ensure that a detrimental shift in the
oxygen distribution (i.e., a shift causing
more low oxygen levels) at either the
low end (10th percentile) or the center
(50th percentile) of the dissolved
oxygen distribution has not occurred.
Median HSI is expected to be zero or
higher, allowing the annual cohort of
juvenile Atlantic Sturgeon to maintain
or increase its biomass, when the 10th
percentile of oxygen saturation is at
least 66% and the 50th percentile, or
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median, of oxygen saturation is at least
74%. Therefore, the EPA expects oxygen
levels will not impair juvenile Atlantic
Sturgeon during the Juvenile
Development season if the 10th
percentile of oxygen saturation is at
least 66% and the 50th percentile of
oxygen saturation is at least 74%.
Criteria Development for Spawning and
Larval Development and Overwintering
Seasons
The Atlantic Sturgeon cohort model
described above relies on experimental
studies that were conducted using
juvenile Atlantic Sturgeon and therefore
provide information that is most
relevant to juvenile growth and
survival.62 Additionally, the underlying
studies allocated most experimental
treatments to water temperatures
between 12 °C and 28 °C, with only a
single experimental treatment at 6 °C
and none at lower water temperatures.63
The EPA’s cohort modeling approach
therefore does not apply to spawning
and larval development lifestages and
has minimal relevance to the
overwintering period. Accordingly, the
EPA did not use the cohort model to
derive criteria for the Spawning and
Larval Development or the
Overwintering seasons.
Instead, the EPA concluded that
Atlantic Sturgeon larvae were likely to
be as sensitive to low dissolved oxygen
as juvenile Atlantic Sturgeon 64 and that
overwintering juveniles have
temperature-limited metabolism and
therefore have similar or slightly lower
oxygen requirements than juveniles in
warmer waters (e.g., summer water
temperatures).65 Thus, the EPA
determined that the percent oxygen
saturation threshold that would be
protective of juveniles experiencing
stressful (high) water temperatures
during the Juvenile Development season
would also be protective of larvae and
overwintering juveniles not
experiencing high water temperatures.
Therefore, the EPA expects oxygen
levels will not impair Atlantic Sturgeon
when the 10th percentile of oxygen
saturation is at least 66% during the
Spawning and Larval Development and
Overwintering seasons. The EPA notes
that from 2002–2022, the median
62 Experimental data are from Campbell and
Goodman 2004 and Niklitschek and Secor 2009a.
63 Niklitschek and Secor 2009a.
64 Stoklosa et al. (2018); United States
Environmental Protection Agency. (2000). Ambient
Aquatic Life Water Quality Criteria for Dissolved
Oxygen (Saltwater): Cape Cod to Cape Hatteras.
Document ID: EPA–822–R–00–012. November 2000.
https://www.epa.gov/sites/default/files/2018-10/
documents/ambient-al-wqc-dissolved-oxygen-capecode.pdf.
65 Niklitschek and Secor (2009a, 2009b).
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oxygen level during the Spawning and
Larval Development and Overwintering
seasons was well above levels expected
to negatively impact either Atlantic
Sturgeon or other oxygen-sensitive
species. Therefore, the EPA concluded
that a second criterion for a 50th
percentile was not needed during these
seasons.
Criteria Expressed as Percent Oxygen
Saturation
Finally, the EPA derived the proposed
criteria in terms of percent oxygen
saturation, rather than in units of
concentration (such as milligrams per
liter or mg/L) for two main reasons.66
First, physiological effects of oxygen on
aquatic organisms are directly related to
percent oxygen saturation and indirectly
related to dissolved oxygen
concentration. As noted by Niklitschek
and Secor (2009a), percent oxygen
saturation or partial pressure are the
most biologically relevant measures of
oxygen because they determine the
maximum rate at which aquatic
organisms may obtain oxygen from the
water. Second, percent oxygen
saturation varies with water temperature
less than dissolved oxygen
concentration. Because oxygen
solubility is higher in cold water than
warm water, dissolved oxygen
concentrations are often much higher in
cold water. The strong negative
relationship between dissolved oxygen
concentration and temperature can
complicate the interpretation of
seasonal dissolved oxygen patterns. For
example, in the Delaware River,
dissolved oxygen concentrations
increase quickly during fall as
temperatures decrease, even though
percent saturation increases more
slowly. In this example, the increasing
oxygen concentration gives the
appearance that oxygen availability to
aquatic organisms is increasing more
rapidly than it is actually increasing.
For Atlantic Sturgeon, this means that
low levels of percent oxygen saturation
may continue to impact growth and
survival even though dissolved oxygen
concentrations increase. Given this
relationship between temperature and
dissolved oxygen concentration, criteria
expressed as concentration will be
above or below the protective threshold
at various times of the year as
66 Percent oxygen saturation and dissolved
oxygen concentration are two different ways to
measure oxygen levels in water. Dissolved oxygen
concentration is the amount of oxygen dissolved in
the water, typically represented as milligrams of
oxygen per liter of water. Percent oxygen saturation
is the ratio, expressed as a percentage, of the
dissolved oxygen concentration in the water to the
dissolved oxygen concentration when at
equilibrium with the atmosphere.
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temperature changes, whereas criteria
expressed as percent oxygen saturation
can be protective throughout the year.
2. Proposed Dissolved Oxygen Criteria
The EPA’s proposed dissolved oxygen
criteria cover three distinct seasons
based largely on Atlantic Sturgeon early
life stages and are intended to protect all
oxygen-sensitive species in the
Delaware River, as explained above. The
Spawning and Larval Development
season occurs between March 1st and
June 30th and captures a comprehensive
range of resident aquatic species’
spawning periods.67 The Juvenile
Development season occurs between
July 1st and October 31st and captures
critical early life stage growth and
development for young-of-the-year
Atlantic Sturgeon. The Overwintering
season occurs between November 1st
and February 28th (or 29th, in a leap
year), when juvenile Atlantic Sturgeon
growth is limited by low water
temperatures.
Each season has water quality criteria
that each consist of three components:
magnitude, duration, and exceedance
frequency. The magnitude component
indicates the required level of dissolved
oxygen in the water, which in this
proposal is presented in units of percent
oxygen saturation. The duration
component specifies the time period
over which water quality is averaged
before comparison with the criteria
magnitude; in this proposal, the
duration is a daily average.68 The
exceedance frequency component
specifies how often (e.g., percentage of
the time) each criterion can be exceeded
in each season while still ensuring that
the use is protected. For this proposed
rulemaking, the exceedance frequency is
determined based on the dissolved
oxygen percentile from which the
magnitude is derived (i.e., the 10th
percentile can be exceeded 10% of the
time, which for a season consisting of
123 days is 12 cumulative days of
exceedance). For dissolved oxygen, an
exceedance occurs when the oxygen
level in the water is below the criterion
value.
In this proposed rulemaking, the
Spawning and Larval Development and
Overwintering seasons each have a
single, identical dissolved oxygen
criterion with a magnitude of 66%
88325
oxygen saturation, a daily average
duration, and a 10% exceedance
frequency (which allows for up to 12
days of cumulative exceedance during
each of these two seasons) (Table 6 of
this preamble). The Juvenile
Development season has two
individually applicable dissolved
oxygen criteria that together define a
protective seasonal distribution of
percent oxygen saturation. The criteria
differ in both magnitude and
exceedance frequency and both levels
must be attained. The first Juvenile
Development criterion defines the lower
end of the distribution of oxygen levels
and consists of a magnitude of 66%
oxygen saturation, a daily average
duration, and a 10% exceedance
frequency (which allows for up to 12
days cumulative exceedance during the
season). The second Juvenile
Development criterion defines the
center of the distribution and consists of
a magnitude of 74% oxygen saturation,
a daily average duration, and a 50%
exceedance frequency (which allows for
up to 61 days cumulative exceedance
during the season) (Table 6 of this
preamble).
TABLE 6—THE EPA’S PROPOSED DISSOLVED OXYGEN CRITERIA
Magnitude
(percent
oxygen
saturation)
Season
Spawning and Larval Development (March 1–June
30).
Juvenile Development (July 1–October 31) ...............
Overwintering (November 1–February 28/29) ............
Exceedance frequency
66
Daily verage ...................................
10% (12 Days Cumulative).
66
74
66
Daily Average .................................
Daily Average .................................
Daily Average .................................
10% (12 Days Cumulative).
50% (61 Days Cumulative).
10% (12 Days Cumulative).
During the criteria derivation process,
the EPA made several decisions based
on the best available sound scientific
information to ensure the dissolved
oxygen criteria would be protective of
the applicable and proposed aquatic life
designated uses. In this section, the EPA
presents three alternative options the
Agency considered. For each
alternative, the EPA examined
information currently available at the
time of this proposal. The EPA has
concerns about whether each alternative
would be protective of the aquatic life
designated uses that include
propagation; therefore, the EPA did not
include any of these alternatives as part
of its lead proposed criteria. However,
the EPA requests comment and
additional information on whether and
how one or more of these alternatives
could protect the applicable and
proposed aquatic life designated uses in
the specified zones of the Delaware
River and if so, what anticipated
benefits would be associated with the
alternative compared to the EPA’s
proposed criteria.69
Alternative 1: Dissolved Oxygen
Criteria Expressed as Concentration
(mg/L).
The EPA’s proposed dissolved oxygen
criteria are expressed as percent oxygen
saturation, as described in section
IV.C.1 of this preamble. However, the
EPA recognizes that some stakeholders
might be more familiar with dissolved
oxygen criteria expressed as
concentration or might have other
reasons for preferring criteria expressed
as concentration. The EPA is seeking
comment on whether dissolved oxygen
criteria expressed as concentration
(mg/L) would be protective of oxygensensitive species during each season.
To calculate Juvenile Development
season criteria expressed as
concentration (mg/L), the EPA followed
an analogous approach to the method
used for determining criteria as percent
oxygen saturation, as explained in
section IV.C.1 of this preamble. The
EPA used quantile generalized additive
models relating seasonal percentiles of
dissolved oxygen concentration to the
expected median habitat suitability
index (HSI). The EPA selected as the
alternative criteria values the dissolved
67 Stoklosa et al. (2018); Delaware River Basin
Commission (2015).
68 The EPA selected a daily average duration
because it is a readily measurable indicator of the
oxygen levels at a daily timescale. The daily average
is protective because variability of dissolved oxygen
levels on a single day is small in the Delaware
River.
69 More information is available in the associated
document, Technical Support Document for the
Proposed Rule: Water Quality Standards to Protect
Aquatic Life in the Delaware River.
3. Alternative Options Considered
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oxygen concentration for which the
expected median HSI is zero (Table 7 of
this preamble).
To calculate dissolved oxygen criteria
expressed as concentration for the
Spawning and Larval Development and
Overwintering seasons, the EPA started
with the criteria computed as percent
oxygen saturation (Table 6 of this
preamble) and converted each of these
to a concentration using each of the
following two approaches, which
differed based on water temperature
assumptions.70 The EPA’s first approach
uses the 90th percentile of water
temperatures in each season, whereas
the second approach uses the average
water temperature in each season.71 The
90th percentile approximates the
highest water temperature in each
season, which corresponds to when
dissolved oxygen levels are generally at
their lowest and therefore impacts to
aquatic life are most likely to occur. In
the Delaware River, the highest
temperatures in the Spawning and
Larval Development season occur in late
June and the highest temperatures in the
Overwintering season occur in early
November. On the other hand, the EPA’s
second approach using an average water
temperature results in the concentration
that minimizes the magnitude of
deviations in either direction from the
protective level across the season.
Because the average water temperature
is lower than the 90th percentile water
temperature, the EPA’s second approach
resulted in higher dissolved oxygen
concentrations than the first approach
(Table 7 of this preamble).
In table 7 below, the EPA leads with
alternative criteria based on the 90th
percentile water temperatures because
existing dissolved oxygen criteria
guidance and criteria derivation efforts
in other states have commonly focused
on the warmest conditions that occur,
which are the most critical for
mitigating impacts to aquatic life due to
low oxygen.72 For consideration, the
EPA presents alternative criteria based
on average water temperatures in
parentheses.
TABLE 7—ALTERNATIVE 1: DISSOLVED OXYGEN CRITERIA EXPRESSED AS CONCENTRATION
[mg/L]
Water temperature
(°C)
Season
Spawning and Larval Development (March
1–June 30).
Juvenile Development (July 1–October 31) ...
N/A + ................................................................
Overwintering (November 1–February 28/29)
Magnitude
(mg/L)
Duration
Exceedance frequency
* 23.3 (14.7)
* 5.6 (6.7)
Daily Average ........................
10% (12 Days Cumulative).
+ N/A
5.4
Daily Average
* 7.0 (8.3)
Daily Average ........................
50% (61 Days Cumulative).
Daily Average ........................
10% (12 Days Cumulative).
6.1
* 12.4 (5.6)
10% (12 Days Cumulative).
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* The 90th percentile of seasonal water temperature and corresponding criterion is used for the main estimate, while the average water temperature and corresponding criterion is shown in parentheses.
+ Water temperature is not applicable during the Juvenile Development season because the criteria magnitudes are derived from the EPA’s Atlantic Sturgeon cohort model, described in section IV.C.1 of this preamble.
Concentration-based criteria derived
using the EPA’s first approach (based on
the 90th percentile water temperatures)
would be equivalent to the EPA’s
proposed 66% oxygen saturation when
water temperature is near the 90th
percentile temperature and oxygen is
near the lowest point in each season.
However, during periods in each season
when water temperature is lower than
the 90th percentile temperature, the
concentration-based criteria would be
below the level that is equivalent to the
EPA’s proposed 66% oxygen saturation
level. For example, when water
temperature is 2 °C in mid-winter,
oxygen saturation is 66% when the
dissolved oxygen concentration is 9.1
mg/L. The EPA therefore has concerns
about whether dissolved oxygen criteria
expressed as concentration for this
alternative would be protective for the
Spawning and Larval Development and
Overwintering seasons. Similar to the
first approach, the concentration
derived using the EPA’s second
approach (average water temperature) is
also below the level that is equivalent to
66% oxygen saturation when water
temperature is below the seasonal
average. During periods in each season
when the water temperature is warmer
than the average, concentrations
calculated using the EPA’s second
approach would result in an oxygen
saturation higher than 66%.73
The EPA provided the concentrations
in table 7 of this preamble that result
from the methods described above to
help facilitate public comment. The
EPA also requests public input and
supporting information about other
ways the Agency could develop
dissolved oxygen criteria expressed as
concentration—particularly for the
Spawning and Larval Development and
Overwintering seasons—to protect the
relevant aquatic life uses in accordance
with the CWA.
Alternative 2: Single Dissolved
Oxygen Criterion During the Juvenile
Development Season with a 10%
Exceedance Frequency.
The EPA’s proposed dissolved oxygen
criteria for the critical Juvenile
Development season consist of two
values—one that may be exceeded 10%
of the time and one that may be
exceeded 50% of the time—that must
both be met during the season, as
explained in section IV.C.1 of this
preamble. However, the EPA recognizes
that some stakeholders might prefer the
simpler criteria framework a single
criterion would afford or may have
other reasons for preferring a single
value.
70 The EPA assumed salinity = 0 for each
conversion from percent oxygen saturation to
concentration in the Spawning and Larval
Development and Overwintering seasons.
71 Seasonal 90th percentile and mean water
temperature were calculated using the daily
climatology computed for Chester for March 1,
2012–June 30th, 2022, for the Spawning and Larval
Development season and November 1, 2011–
February 28, 2022, for the Overwintering season.
72 United States Environmental Protection
Agency. (2000). Ambient Aquatic Life Water
Quality Criteria for Dissolved Oxygen (Saltwater):
Cape Cod to Cape Hatteras. Document ID: EPA–
822–R–00–012. November 2000. https://
www.epa.gov/sites/default/files/2018-10/
documents/ambient-al-wqc-dissolved-oxygen-capecode.pdf; Batiuk, R.A., Breitburg, D.L., Diaz, R.J.,
Cronin, T.M., Secor, D.H., and Thursby, G. (2009).
Derivation of habitat-specific dissolved oxygen
criteria for Chesapeake Bay and its tidal tributaries.
Journal of Experimental Marine Biology and
Ecology 381: S204–S215. https://doi.org/10.1016/
j.jembe.2009.07.023.
73 More information on dissolved oxygen trends
in the specified zones of the Delaware River is
available in the associated rule documents,
Technical Support Document for the Proposed
Rule: Water Quality Standards to Protect Aquatic
Life in the Delaware River and Economic Analysis
for the Proposed Rule: Water Quality Standards to
Protect Aquatic Life in the Delaware River.
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The EPA is seeking comment and
supporting information on applying a
single dissolved oxygen criterion with a
10% exceedance frequency during the
Juvenile Development season, including
whether criteria expressed with a single
criterion would protect the applicable
and proposed aquatic life designated
uses. This could mean applying a single
criterion of 66% oxygen saturation (or
5.4 mg/L, if expressed as concentration)
with a 10% exceedance frequency for
the Juvenile Development season. The
Overwintering and Spawning and Larval
Development seasons are unaffected by
this alternative.
The EPA also requests public input
and supporting information about other
potential options the Agency could
consider for dissolved oxygen criteria in
the form of a single criterion to protect
the aquatic life uses in accordance with
the CWA.
Alternative 3: Inclusion of a 1-in-3Year Interannual Exceedance
Frequency.
The EPA’s proposed criteria do not
include an interannual exceedance
frequency and therefore would need to
be met every year. However, the EPA
recognizes that some stakeholders might
prefer criteria with an interannual
exceedance frequency to help
accommodate the impact of
environmental variability on dissolved
oxygen conditions in the specified
zones of the Delaware River. The EPA
is seeking comment and supporting
information on the addition of a 1-in-3year interannual exceedance frequency
as part of the dissolved oxygen criteria.
The EPA is particularly interested in
how and why this approach would
protect the applicable and current
aquatic life uses.
If a 1-in-3-year interannual
exceedance frequency were included as
part of the dissolved oxygen criteria, it
88327
would mean that in any three-year
period, all criteria would need to be
attained in at least two years. An
exceedance would occur in any year
where one or more of the criteria were
not attained. The following two
examples describe how a 1-in-3-year
interannual exceedance frequency could
function.
Example 1: If, in a given year, the
dissolved oxygen during the Juvenile
Development season fell below 66%
saturation more than 10% of the time,
then that year would not meet the
Juvenile Development 10th percentile
criterion. Therefore, that year would
count as one year of exceedance towards
the 1-in-3-year interannual exceedance
frequency. If another criterion, for
example the Spawning and Larval
Development criterion, was not met in
that same year, then it would still only
count as one year of exceedance despite
the fact that two criteria were not met
that year (Table 8 of this preamble).
TABLE 8—EXAMPLE 1 SCENARIO WHERE DISSOLVED OXYGEN CRITERIA WITH THE 1-IN-3-YEAR INTERANNUAL
EXCEEDANCE FREQUENCY ARE MET
Was the seasonal criterion met?
Season
Year 1
Spawning and Larval Development ......................................................
Juvenile Development—10th Percentile ...............................................
Juvenile Development—50th Percentile ...............................................
Overwintering ........................................................................................
Does the Full Year Meet Criteria? ........................................................
Year 2
No ...............................
No ...............................
Yes .............................
Yes .............................
No ...............................
criterion. If the following year, the
Juvenile Development season fell below
74% saturation more than 50% of the
time, then that year would not meet the
Juvenile Development 50th percentile
criterion (Table 9 of this preamble). In
Example 2: If, in a given year, the
dissolved oxygen during the Juvenile
Development season fell below 66%
saturation more than 10% of the time,
then that year would not meet the
Juvenile Development 10th percentile
Yes
Yes
Yes
Yes
Yes
.............................
.............................
.............................
.............................
.............................
Year 3
Yes.
Yes.
Yes.
Yes.
Yes.
this scenario, the first and second year
in the three-year period both did not
meet the criteria; therefore, the
interannual exceedance frequency was
not met.
TABLE 9—EXAMPLE 2 SCENARIO WHERE DISSOLVED OXYGEN CRITERIA WITH THE 1-IN-3-YEAR INTERANNUAL
EXCEEDANCE FREQUENCY ARE NOT MET
Was the seasonal criterion met?
Season
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Spawning and Larval Development ......................................................
Juvenile Development—10th Percentile ...............................................
Juvenile Development—50th Percentile ...............................................
Overwintering ........................................................................................
Does the Full Year Meet Criteria? ........................................................
The EPA has historically considered it
appropriate to apply a 1-in-3-year
exceedance frequency in the context of
aquatic life criteria for toxic pollutants,
based on the ability of aquatic
ecosystems to recover from criteria
exceedances and natural variations in
flow and the concentrations of the
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Year 1
Year 2
Yes .............................
No ...............................
Yes .............................
Yes .............................
No ...............................
Yes .............................
Yes .............................
No ...............................
Yes .............................
No ...............................
pollutant in a waterbody.74 However,
74 Stephen, C.E., Mount, D.I., Hansen, D.J.,
Gentile, J.R., Chapman, G.A., and Brungs, W.A.
(1985). Guidelines for Deriving Numerical National
Water Quality Criteria for the Protection of Aquatic
Organisms and Their Uses. United States
Environmental Protection Agency. Document ID:
PB85–227049. https://www.epa.gov/sites/default/
files/2016-02/documents/guidelines-water-qualitycriteria.pdf; United States Environmental Protection
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Year 3
Yes.
Yes.
Yes.
Yes.
Yes.
the EPA does not typically apply this
construct to criteria for conventional
water quality parameters like dissolved
Agency. (2023). Proceedings from the EPA
Frequency and Duration Experts Workshop:
September 11–12, 2019. Document ID: EPA–820–R–
23–002. February 2023. https://www.epa.gov/
system/files/documents/2023-02/proceedingsfrequency-duration-workshop.pdf.
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oxygen due to inherent differences
between these parameters and toxic
pollutants. For example, dissolved
oxygen is typically not directly
regulated in the same manner as toxic
pollutants because low dissolved
oxygen conditions (such as hypoxia) are
a symptom of a related issue, such as
nutrient or ammonia pollution.75 The
EPA also requests public input and
supporting information regarding any
scientific approaches that can be used to
predict the impact of periodic low
oxygen levels on populations of aquatic
organisms.
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V. Endangered Species Act
Consultation
Section 7(a)(2) of the Endangered
Species Act (ESA) requires that each
Federal Agency ensure that any action
authorized, funded, or carried out by
such Agency is not likely to jeopardize
the continued existence of any
endangered or threatened species or
result in the destruction or adverse
modification of critical habitat. Pursuant
to section 7(a)(2) of the ESA, the EPA
will consult with NOAA Fisheries
concerning this rulemaking action
proposing a designated aquatic life use
including propagation and associated
dissolved oxygen criteria in the
specified zones of the Delaware River.
The EPA will work closely with NOAA
Fisheries to ensure that any WQS the
Agency finalizes are not likely to
jeopardize the continued existence of
any endangered or threatened species or
result in the destruction or adverse
modification of designated critical
habitat in the specified zones of the
Delaware River. As a result of this
consultation, the EPA may modify some
provisions of this proposed rule.
VI. Applicability
The EPA is proposing a Federal
designated use that would apply in New
Jersey and Pennsylvania, in addition to
those states’ designated uses that are
already applicable. This means that for
the specified zones of the Delaware
River, the EPA is proposing to
supplement, rather than replace, New
Jersey’s and Pennsylvania’s currently
applicable aquatic life designated uses.
Therefore, New Jersey’s and
Pennsylvania’s currently applicable
aquatic life designated uses would
remain applicable for CWA purposes.
75 United States Environmental Protection
Agency. (2000). Ambient Aquatic Life Water
Quality Criteria for Dissolved Oxygen (Saltwater):
Cape Cod to Cape Hatteras. Document ID: EPA–
822–R–00–012. November 2000. https://
www.epa.gov/sites/default/files/2018-10/
documents/ambient-al-wqc-dissolved-oxygen-capecode.pdf.
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Those states’ current water quality
criteria associated with those uses
would also remain applicable for CWA
purposes, with the exception of any
aquatic life criteria for dissolved
oxygen, which would be replaced by the
criteria that the EPA promulgates
through this rulemaking, if finalized.76
The EPA concluded that this approach
was the best way to make clear which
of the states’ WQS would and would not
be revised by this rulemaking, if
finalized. The EPA requests comment
on this approach.
In addition, the EPA is proposing
dissolved oxygen criteria that would
replace Delaware’s, New Jersey’s, and
Pennsylvania’s existing dissolved
oxygen criteria for the specified zones of
the Delaware River. The EPA notes that
there are aquatic life criteria for
pollutants and parameters other than
dissolved oxygen that are in effect for
CWA purposes—not only in the zones
covered by this proposed rulemaking,
but also for other zones of the Delaware
River that already include aquatic life
propagation as a designated use; those
criteria are not impacted by this
rulemaking.
Since the EPA is only proposing to
promulgate revised dissolved oxygen
criteria for the specified zones of the
Delaware River, Delaware, New Jersey,
and Pennsylvania should evaluate
whether other aquatic life criteria
should similarly be added or revised for
the specified zones or other zones of the
Delaware River. One way these states
can review their WQS is through the
triennial review process. As explained
in section III of this preamble, states
must review their WQS at least once
every three years and, if appropriate,
revise standards or adopt new standards
(40 CFR 131.20(a)). The EPA
recommends that Delaware, New Jersey,
and Pennsylvania review their existing
aquatic life criteria during their next
triennial review to determine if new or
revised aquatic life criteria would be
appropriate to protect all applicable
aquatic life designated uses, including
any Federal designated use that the EPA
may promulgate as part of a final rule.
VII. Conditions Where Federal Water
Quality Standards Would Not Be
Promulgated or Would Be Withdrawn
As noted, under the CWA, states and
authorized tribes have the primary
76 In the December 1, 2022, Administrator’s
Determination, the EPA determined that revised
dissolved oxygen criteria are necessary to protect a
propagation designated use. This proposed
rulemaking includes dissolved oxygen criteria that
are protective of all life stages of resident and
migratory aquatic life species in the Delaware River
(section IV.C. of this preamble).
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responsibility for developing and
adopting WQS for their navigable waters
(CWA section 303(a) through (c)).
Although the EPA is proposing a revised
aquatic life designated use and
protective dissolved oxygen criteria for
the specified zones of the Delaware
River, each state retains the option to
adopt and submit to the EPA for review
its own revised designated use and
dissolved oxygen criteria that are
consistent with CWA section 303(c) and
the EPA’s implementing regulation to
address the EPA’s Administrator’s
Determination.
A. Conditions Where Federal Standards
Would Not Be Promulgated
If Delaware, New Jersey, and
Pennsylvania adopt and submit revised
WQS that addresses the EPA’s
December 1, 2022, Administrator’s
Determination, and the EPA approves
those WQS before finalizing this
proposed rulemaking, then a Federal
promulgation would no longer be
required under the CWA. Similarly, if
one state adopts and submits WQS
consistent with this proposed
rulemaking, and the EPA approves those
WQS before finalizing this proposed
rulemaking, then a Federal
promulgation would no longer be
required under the CWA for that state.
B. Conditions Where Federal Standards
Would Be Withdrawn
If the EPA finalizes this proposed
rulemaking and Delaware, New Jersey,
and Pennsylvania subsequently adopt
and submit revised WQS to the EPA,
and the EPA approves those WQS, then
the EPA would undertake a rulemaking
to withdraw the federally promulgated
use and/or dissolved oxygen criteria (40
CFR 131.21(c)). Similarly, if one state
adopts and submits revised WQS to the
EPA, and the EPA approves those WQS,
then the EPA would undertake a
rulemaking to withdraw the federally
promulgated WQS for that state.
If Delaware’s, New Jersey’s, and/or
Pennsylvania’s adopted dissolved
oxygen criteria are as stringent or more
stringent than the federally promulgated
criteria, then that state’s criteria would
immediately become the CWAapplicable criteria upon the EPA’s
approval. If Delaware’s, New Jersey’s,
and/or Pennsylvania’s adopted
dissolved oxygen criteria are less
stringent than the federally promulgated
criteria, and the EPA approves those
less stringent criteria, then those EPAapproved criteria would become the
applicable criteria for CWA purposes
only after the EPA withdraws its
federally promulgated criteria for the
relevant state(s).
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attaining the applicable designated use
and dissolved oxygen criterion.
VIII. Alternative Regulatory
Approaches and Implementation
Mechanisms
A. Water Quality Standards Variances
B. NPDES Permit Compliance Schedules
The EPA’s regulations at 40 CFR
122.47 and 131.15 address how
permitting authorities can use schedules
for compliance with a water-qualitybased effluent limitation (WQBEL) in an
NPDES permit, if the discharger needs
time to undertake an enforceable
sequence of actions—such as facility
upgrades or operation changes—leading
to compliance with the WQBEL. The
EPA’s regulation at 40 CFR 122.47
allows states authorized to administer
the NPDES program to include
compliance schedules in NPDES
permits, when appropriate and where
authorized by the state’s WQS, provided
the compliance schedule authorizing
provision was approved by the EPA.
Such compliance schedules may be
used to implement any CWA-effective
WQS, including any WQS that the EPA
promulgates as part of a final rule.
A WQS variance is a time-limited
designated use and criterion, for a
specific pollutant or water quality
parameter, that reflects the highest
attainable condition (HAC) during the
term of the WQS variance (40 CFR
131.3(o)). WQS variances can be used to
incrementally improve water quality
where the designated use and criterion
are unattainable for a period of time.
The state would need to demonstrate
that attaining the applicable designated
use and dissolved oxygen criterion
would not be feasible for a period of
time (i.e., during the term of the WQS
variance) because of one of the factors
specified in 40 CFR 131.14(b)(2)(i)(A)
and specify the actions that will be
taken to make incremental water quality
improvements during the term of the
WQS variance.
If Delaware, New Jersey, and/or
Pennsylvania choose/s to adopt a WQS
variance, the state/s must specify in the
WQS variance the term and the interim
requirements of the WQS variance. The
term must be justified by describing the
pollutant control activities expected to
occur over that term to achieve the
HAC. The interim requirements must be
a quantitative expression that reflects
the HAC using one of the options
provided at 40 CFR 131.14(b)(1)(ii).
WQS variances adopted in accordance
with 40 CFR 131.14 and approved by
the EPA for CWA purposes provide a
legal avenue for states to write NPDES
permit limits that are based on the HAC
during the term of the WQS variance,
while simultaneously implementing
controls to make incremental water
quality improvements toward ultimately
C. Clean Water Act Section 303(d)/
305(b) Water Quality Assessments
If the EPA promulgates revised
aquatic life WQS for the specified zones
of the Delaware River and they become
effective for CWA purposes, Delaware,
New Jersey, and Pennsylvania will have
an obligation under CWA sections
303(d) and 305(b) to assess whether the
WQS are being attained. The EPA
anticipates there may be a period of
time immediately after promulgation of
the revised WQS when the WQS will
not be attained because the actions and
procedures required to achieve
compliance will take time to implement.
In this scenario, any of the relevant
zones not attaining the WQS should be
classified as impaired on the relevant
303(d)/305(b) Integrated Report(s) (IR)
that is submitted to the EPA for review.
Per the CWA and the EPA’s
implementing regulations, waters that
are assessed as impaired by a pollutant
typically require the development of a
Total Maximum Daily Load (TMDL),
which is a regulatory planning tool
designed to restore water quality via
allocations of pollutant reductions to
relevant point and non-point sources.
The EPA regulations also recognize that
other pollution control requirements
may obviate the need for a TMDL.
Specifically, impaired waters do not
require a TMDL if: (1) technology-based
effluent limitations required by the
CWA; (2) more stringent effluent
limitations required by a state, local, or
Federal authority; or (3) other pollution
control requirements (e.g., best
management practices) required by a
state, local, or Federal authority are
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The Federal WQS regulations at 40
CFR part 131 provide several
approaches that Delaware, New Jersey,
and Pennsylvania could use at each
state’s discretion when implementing or
deciding how to implement the
federally promulgated dissolved oxygen
criteria, if finalized. The EPA has
identified two approaches—WQS
Variances and NPDES Permit
Compliance Schedules—that might be
of particular interest for the states
covered by this proposed rulemaking.
Additionally, the EPA included a
discussion about CWA section 303(d)/
305(b) water quality assessments to
clarify potential options that may be
available to states in the specific
circumstances relevant to this
rulemaking.
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88329
stringent enough to implement
applicable WQS (40 CFR 130.7(b)(1)).
Impaired waters that do not require a
TMDL because they satisfy one of these
alternatives are commonly referred to as
Category 4b waters, as described in the
EPA’s Integrated Reporting Guidance for
CWA sections 303(d), 305(b), and 314.77
DRBC developed a model to evaluate
sources of pollution that affect dissolved
oxygen levels in the specified zones of
the Delaware River and concluded that
point sources are the primary
contributor to oxygen depletion within
those zones.78 DRBC therefore
concluded that further controls on point
sources are needed to achieve dissolved
oxygen water quality conditions that
support aquatic life designated uses that
include propagation in the specified
zones. The EPA’s economic analysis
evaluates point source controls that are
expected to result in dissolved oxygen
levels that meet EPA’s proposed
criteria.79 If, after finalization of this
rulemaking, DRBC, Delaware, New
Jersey, or Pennsylvania require effluent
limitations and/or other pollution
control requirements that the EPA
agrees are stringent enough to
implement the final dissolved oxygen
criteria, the specified zones may be a
candidate for Category 4b in future IRs.
The EPA will work with Delaware, New
Jersey, and Pennsylvania, in
consultation with DRBC, on future IRs
to determine the appropriate assessment
status for the waters that are subject to
this rulemaking.
IX. Economic Analysis
The EPA conducted an economic
analysis to evaluate the potential costs
and benefits associated with this
proposed rulemaking. In the high-level
summary of the EPA’s economic
analysis below, the EPA first describes
a baseline scenario that is intended to
characterize the world in the absence of
the EPA’s proposed rule. Next, the EPA
describes development of a policy
scenario based on potential pollution
control actions that, if implemented, can
be expected to meet the EPA’s proposed
dissolved oxygen criteria. Finally, the
EPA evaluates the anticipated costs and
benefits associated with the policy
scenario and the EPA’s proposed
criteria. More details and information
77 The EPA’s Integrated Reporting Guidance is
available at: https://www.epa.gov/tmdl/integratedreporting-guidance-under-cwa-sections-303d-305band-314.
78 Delaware River Basin Commission (2022a,
2022b).
79 More details are available in the document,
Economic Analysis for the Proposed Rule: Water
Quality Standards to Protect Aquatic Life in the
Delaware River.
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are available in the associated
document, Economic Analysis for the
Proposed Rule: Water Quality Standards
to Protect Aquatic Life in the Delaware
River.
A. Baseline for the Analysis
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The baseline is intended to
characterize the world in the absence of
the EPA’s proposed rule. The EPA
typically assumes full compliance with
existing regulations and requirements—
including CSO long-term control plans
(LTCPs)—even if they are not yet fully
implemented, as a basis for estimating
the cost and benefits of proposed
regulations. This baseline approach
ensures that the cost and benefits of the
existing regulations and requirements
are not double counted.
In this economic analysis, the EPA
assumes that without the proposed rule,
the less stringent WQS (that do not
support aquatic life propagation)
currently in effect for CWA purposes
would remain in effect (section III.D. of
this preamble). Accordingly, the EPA
assumes that water quality conditions in
the specified zones of the Delaware
River, particularly during the Juvenile
Development season (July 1–October
31), would continue to experience low
oxygen levels that do not support
aquatic life propagation, even with
implementation of existing and planned
CSO LTCPs.80 Along the specified zones
of the Delaware River, there are three
combined sewer systems with CSO
LTCPs that are relevant for
consideration by the EPA as part of the
baseline. The Philadelphia Water
Department, Camden County Municipal
Utilities Authority, and Delaware
County Regional Water Quality Control
Authority all have LTCPs that are either
approved or in progress.81 The EPA
expects implementation of these LTCPs,
when finalized, to occur regardless of
the EPA’s proposed rule. Therefore, the
EPA included estimated CSO volume
reductions for these three dischargers as
part of the baseline for this economic
analysis.
80 While the EPA normally assumes full
compliance with existing LTCPs, for this proposed
rulemaking, the EPA is also assuming full
compliance with planned LTCPs. Because planned
LTCPs are not final and therefore are subject to
change, this adds uncertainty to the baseline
conditions.
81 Delaware River Basin Commission (2022a);
DELCORA. (2023). Combined Sewer System:
DELCORA CSO LTCP. https://www.delcora.org/
combined-sewer-systems/delcora-cso-ltcp/;
Philadelphia Water Department. (2023). CSO Long
Term Control Plan. https://water.phila.gov/
reporting/ltcp/; State of New Jersey Division of
Water Quality. (2023). Long Term Control Plan
Submittals. https://www.nj.gov/dep/dwq/csoltcpsubmittals.htm.
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DRBC modeled the effect of pollution
reduction on dissolved oxygen levels in
the Delaware River and provided the
EPA with water quality simulation
results under both baseline and
‘‘restored’’ conditions for the years
2012, 2018, and 2019.82 Baseline
simulations predict water quality
conditions associated with the discharge
of actual wastewater treatment plant
(WWTP) flows at existing levels of
treatment and after full implementation
of LTCPs. The restored simulations
predict water quality conditions
associated with the discharge of actual
WWTP flows at treatment levels that
include additional effluent treatment
and after full implementation of LTCPs.
Of the three available years (2012,
2018, and 2019), the EPA selected the
2019 year as representative of the most
typical conditions in the relevant zones
of the Delaware River. In comparison,
2012 had atypically poor conditions
(low percent oxygen saturation, high
water temperature), while 2018 had
atypically good conditions (high percent
oxygen saturation, low water
temperature). Therefore, model runs
used in this economic analysis are based
on 2019 conditions.
B. Development of the Policy Scenario
There is a wide range of potential
paths that Delaware, New Jersey, and
Pennsylvania may choose to take when
implementing the EPA’s proposed WQS.
For this economic analysis, the EPA
relied on available data to develop a
policy scenario based on modeled
pollution controls developed by DRBC
that the EPA expects would meet the
Agency’s proposed dissolved oxygen
criteria. Actual benefits, costs, and
impacts will depend on the choices that
states would make in implementing the
proposed WQS, which may differ from
the policy scenario in this economic
analysis.
The EPA’s proposed dissolved oxygen
criteria apply to three seasons (section
IV.C. of this preamble). Therefore, when
developing a policy scenario for this
proposed rulemaking, the EPA
evaluated potential pollution control
actions that would be expected to meet
the EPA’s criteria in each of the three
seasons. The EPA began by evaluating
water quality monitoring data for the
past decade from two continuous
monitoring stations in the relevant
zones of the Delaware River—Penn’s
Landing in Zone 3 and Chester in Zone
4. Based on the monitoring data, the
EPA expects that the Agency’s proposed
82 The EPA determined that the model runs from
DRBC were sufficient for use in this economic
analysis.
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dissolved oxygen criteria for the
Spawning and Larval Development and
Overwintering seasons will likely be met
without the need for additional WWTP
upgrades or other controls beyond the
baseline conditions (i.e., the LTCPs).
Monitoring data for the Juvenile
Development season indicated that
additional pollution control actions are
likely necessary to meet the EPA’s
proposed criteria in that season. To
develop a policy scenario for the
Juvenile Development season, the EPA
relied on modeled data from DRBC
predicting oxygen levels in 2019 in the
specified zones of the Delaware River
following a set of WWTP pollution
control actions for certain dischargers.
Modeled data for restored conditions are
described in the baseline section above,
while WWTP controls are described in
the cost section below. The EPA expects
that this policy scenario (hereafter, the
‘‘2019 restored scenario’’) will meet the
proposed criteria during the Juvenile
Development season.
C. Potential Costs
The EPA estimated compliance costs
for the proposed WQS based on
estimates for WWTPs to reduce effluent
ammonia nitrogen concentrations and
raise effluent dissolved oxygen
concentrations. Although there are
several causes that contribute to low
dissolved oxygen conditions in the
specified zones of the Delaware River,
DRBC identified ammonia nitrogen
loadings from WWTPs as the leading
cause of oxygen-depletion in the river.83
As a result, for the purpose of this
economic analysis, the EPA assumed
that additional pollution control
technologies implemented at WWTPs is
the most likely way that Delaware, New
Jersey, and Pennsylvania will
implement the proposed WQS.
Therefore, the EPA evaluated WWTP
controls rather than other non-point
source controls for this cost analysis.
The EPA relied on cost information
from several DRBC studies to estimate
the costs of achieving the proposed
WQS.84 DRBC’s 2022 Analysis of
Attainability report categorized WWTPs
as either class A′, A, or B facilities.
DRBC determined that discharges from
Class A′, A, and B facilities have a major
83 Delaware
River Basin Commission (2022a).
Kleinfelder Inc. (2021). Nitrogen Reduction
Cost Estimation Study Final Summary Report.
https://www.nj.gov/drbc/library/documents/
NitrogenReductionCostEstimates_
KleinfelderJan2021.pdf; Kleinfelder Inc. (2023).
Delaware River Basin Commission Nitrogen
Reduction Cost Estimation Study—Supplemental
Cost Addendum 2 Technical Memorandum—Final.
https://www.nj.gov/drbc/library/documents/
NitrogenReductionCostEstimates_Kleinfelder_
aug2023addendum.pdf.
84 Id.;
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impact, a marginal impact, or no
measurable impact on oxygen levels in
the specified zones, respectively. The
EPA’s 2019 restored scenario follows
DRBC’s approach by including the
seven Class A′ and two Class A facilities
and excluded the three Class B
facilities.85
The EPA used WWTP-specific
(capital, operations and maintenance
(O&M)) compliance costs from
Kleinfelder Inc. (2021, 2023) to estimate
compliance costs, based on the
discharger classification. Total
compliance costs include the costs
associated with both of the following:
1. Class A′ Facilities: Costs associated
with reductions in effluent ammonia
nitrogen concentrations to 1.5 mg/L
from May 1 through October 31 and
increases in effluent oxygen
concentrations to a monthly average of
6 mg/L year-round for the seven
WWTPs categorized as Class A′
facilities.
2. Class A Facilities: Costs associated
with reductions in effluent ammonia
nitrogen concentrations to 5 mg/L from
May 1 through October 31 for the two
WWTPs categorized as Class A facilities.
To estimate annualized compliance
costs, the EPA assumed capital costs
occur upfront in 2024 followed by a 5year construction period. Consistent
with Kleinfelder Inc. (2021, 2023), the
EPA assumed O&M costs occur over a
25-year period from 2029 through 2053.
The EPA thus annualized costs over a
30-year analysis period between 2024
and 2053 and discounted all cost values
to 2024, using a 3 percent discount rate.
88331
Table 10 of this preamble presents the
annualized compliance costs associated
with achieving the EPA’s proposed
WQS, using a 3 percent discount rate.
The estimated total annualized
compliance cost across nine WWTPs is
$137.1 million (2022$). These costs vary
considerably between the nine WWTPs,
ranging from $1.9 million at the Lower
Bucks County Joint Municipal Authority
WWTP to $37.6 million at the
Philadelphia Water Department (PWD)
Southwest Water Pollution Control
Plant (2022$). Among the dischargers,
PWD bears the highest proportion of
total costs, with its three facilities’
combined costs accounting for over 50
percent of total costs. Overall, 66
percent of the costs are attributable to
capital and 34 percent are attributable to
O&M.
TABLE 10—ANNUALIZED COMPLIANCE COSTS USING A 3 PERCENT DISCOUNT RATE
[Million 2022$]
Plant
State
Camden County Municipal Utilities Authority ........................................................................
City of Wilmington .................................................................................................................
Delaware County Regional Water Pollution Control Authority .............................................
Gloucester County Utilities Authority ....................................................................................
PWD Northeast Water Pollution Control Plant .....................................................................
PWD Southeast Water Pollution Control Plant .....................................................................
PWD Southwest Water Pollution Control Plant ....................................................................
Hamilton Township ................................................................................................................
Lower Bucks County Joint Municipal Authority ....................................................................
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Total ...............................................................................................................................
D. Potential Benefits
Water quality improvements can have
a wide range of effects on water
resources and the environmental goods
and services that they provide,
including services valued by people
(e.g., recreation, commercial fishing,
public and private property ownership,
existence services such as aquatic life,
wildlife, and habitat designated uses).
Some environmental goods and services
(e.g., commercially caught fish) are
traded in markets, and thus their value
can be directly observed. Other
environmental goods and services (e.g.,
recreation and support of aquatic life)
cannot be bought or sold directly and
thus do not have observable market
values. This second type of
environmental goods and services are
classified as ‘‘non-market.’’ The
estimated changes in the non-market
values of the water resources affected by
the EPA’s proposed WQS (hereafter,
85 Delaware
River Basin Commission (2022a).
EPA has used this benefit transfer
approach on numerous occasions, most recently in
86 The
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NJ
DE
DE
NJ
PA
PA
PA
NJ
PA
Class
..................
..................
..................
..................
..................
..................
..................
..................
..................
........................
A′
A′
A′
A′
A′
A′
A′
A
A
Annualized costs
(millions 2022$)
....................
....................
....................
....................
....................
....................
....................
....................
....................
$16.2
23.9
9.1
4.9
26.2
14.1
37.6
3.3
1.9
........................
137.1
‘‘non-market benefits’’) are additive to
market values (e.g., avoided costs of
producing various market goods and
services).
To value non-market benefits, the
EPA used a benefit transfer approach
based on a meta-analysis of surface
water valuation studies to evaluate the
use and nonuse benefits of improved
surface water quality resulting from
achievement of the EPA’s proposed
WQS in the 2019 restored scenario.86
The benefit transfer approach involves
three main steps:
1. Estimating water quality
improvements associated with
attainment of the EPA’s proposed WQS
relative to the baseline;
2. Translating these improvements
into a water quality index (WQI) that
can be linked to ecosystem services and
uses that are valued by society. The
WQI used for this analysis includes six
parameters: dissolved oxygen, biological
oxygen demand (BOD), fecal coliform
(FC), total nitrogen (TN), total
phosphorus (TP), and total suspended
solids (TSS); and
3. Estimating the dollar value of the
estimated water quality improvements
based on estimates of the public’s
willingness-to-pay (WTP) derived from
a meta-analysis of surface water
valuation studies.
To estimate changes in ecosystem
services provided in the specified zones
of the Delaware River following
attainment of the proposed WQS, the
EPA obtained water quality modeling
data from DRBC, including dissolved
oxygen, TN, and TP levels for various
effluent treatment scenarios. The EPA
used DRBC’s modeled output of
dissolved oxygen levels in the specified
zones following implementation of
effluent controls (described in the cost
section) and based on 2019 conditions
(as described in the policy scenario
the Benefit and Cost Analysis for Proposed
Revisions to the Effluent Limitations Guidelines and
Standards for the Steam Electric Power Generating
Point Source Category, which is available at https://
www.epa.gov/system/files/documents/2023-03/
steam-electric-benefit-cost-analysis_proposed_feb2023.pdf.
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EPA’s proposed WQS.88 Households
may consider waters unaffected by the
EPA’s proposed WQS to be substitute
waters for those affected, and this can
influence what households would be
willing to pay for improvements
associated with the proposed WQS. The
EPA deems waters unaffected by the
proposed WQS within the 100-mile
buffer around each Census block group
as viable substitutes.
The EPA estimated the economic
value of water quality changes using
results of a meta-analysis of 189
estimates of total WTP (including both
use and nonuse values) for water quality
improvements, provided by 59 original
studies conducted between 1981 and
2017. The estimated econometric model
allows calculation of total WTP for
changes in a variety of environmental
services affected by water quality and
valued by people, including changes in
recreational fishing opportunities, other
water-based recreation, and existence
services such as aquatic life, wildlife,
and habitat designated uses. The model
also allows the EPA to adjust WTP
values based on the core geospatial
factors predicted by theory to influence
WTP, including: scale (the size of
affected resources or areas), market
extent (the size of the market area over
which WTP is estimated), and the
availability of substitute waters. The
model also takes into account important
sociodemographic characteristics, such
as population and income, which vary
TABLE 11—DISSOLVED OXYGEN AND spatially.
BIOLOGICAL
OXYGEN
DEMAND
Table 12 in this preamble presents
CHANGES BETWEEN THE BASELINE
estimated household and total
AND 2019 RESTORED SCENARIOS
annualized WTP value for water quality
improvements following attainment of
Percent
the EPA’s proposed WQS, based on a 3
Zone
change from
baseline a
percent discount rate. The total
annualized value of water quality
3 ............................................
10.8
4 ............................................
23.8 improvements from attainment of the
Upper-5 .................................
8.8 proposed WQS is $112.8 million.
section). The EPA used the 2019
restored scenario as the basis for
representing conditions following the
implementation of the proposed WQS,
while making minor adjustments as
needed 87 to ensure that predicted
oxygen levels meet the EPA’s proposed
WQS. This analysis provides insight
into the water quality improvements
and benefits that are likely to result
from implementation of the proposed
WQS. For the remaining parameters
included in the WQI (i.e., BOD, FC, and
TSS), the EPA relied on measured data
at various locations within the specified
zones.
The effluent treatment measures
implemented in response to the
proposed WQS would directly affect the
amount of ammonia nitrogen discharged
to the specified zones of the Delaware
River and therefore also reduce BOD.
However, DRBC’s model does not
account for the changes in BOD. The
EPA approximated BOD concentrations
following effluent treatment by
assuming that baseline BOD
concentrations are reduced by the same
percentage change that dissolved
oxygen improves within each zone (i.e.,
Zone 3, 4, and Upper 5) of the model.
The EPA kept levels for the remaining
parameters (TN, TP, TSS, and FC)
unchanged from baseline conditions.
Table 11 of this preamble summarizes
the percent change in dissolved oxygen
and BOD by zone between the baseline
and the 2019 restored scenario.
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a The percent change for dissolved oxygen
and biological oxygen demand are the same,
but in opposite directions, i.e., the percent decrease in biological oxygen demand concentration is the same as the percent increase
in dissolved oxygen concentration.
To quantify benefits of water quality
improvements, as is consistent with past
practice, the EPA analyzed the values
held by households residing within 100
miles of the specified zones of the
Delaware River for water quality
improvements associated with the
87 Adjustments are detailed in section 4.2 of the
associated document, Economic Analysis for the
Proposed Rule: Water Quality Standards to Protect
Aquatic Life in the Delaware River.
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88 The EPA’s 100-mile radius assumption follows
Viscusi et al. (2008), which states: ‘The survey
defined relevant water quality as residing in a
region that is ‘‘a 2-hour drive or so of your home,
in other words, within 100 miles.’’ About 80% of
all recreational uses of bodies of water are within
such a radius of users’ homes. This 80% figure was
based on data generated by EPA from the 1996
National Survey on Recreation and the
Environment. Data indicates that 77.9% of boating
visits, 78.1% of fishing visits, and 76.9% of
swimming recreational visits are within a 100-mile
radius of a given waterbody. (Citation: Viscusi, W.
K., Huber, J., & Bell, J. (2008). The economic value
of water quality. Environmental and resource
economics, 41(2), 169–187.)
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TABLE 12—ESTIMATED HOUSEHOLD
AND TOTAL ANNUALIZED WILLINGNESS-TO-PAY (WTP) FOR WATER
QUALITY IMPROVEMENTS UNDER THE
EPA’S PROPOSED WATER QUALITY
STANDARDS, USING A 3 PERCENT
DISCOUNT RATE
Average
number of
affected
households
(millions)
Average
annual WTP
per household
(2022$)
Total
annualized
WTP
(millions
2022$, 3%
discount rate)
14.96 .........
$8.18
$112.8
E. Conclusion
The United States Office of
Management and Budget requires that
for ‘‘significant regulatory actions’’ (as
defined in Executive Order 12866 and
as amended and reaffirmed by Executive
Order 14094), that the EPA conduct an
economic analysis. While this proposed
rulemaking was not deemed significant,
the EPA nonetheless conducted an
economic analysis to evaluate the
potential costs and benefits associated
with the WQS in the EPA’s proposed
rule. For this proposed rulemaking, the
EPA determined that the potential
benefits justify the potential costs. The
EPA estimates that the implementation
of additional effluent treatment controls
at certain WWTPs could lead to $137.1
million in annualized costs over 30
years (2022$, 3% discount rate). The
EPA quantified estimated non-market
benefits through average annual
household WTP for water quality
improvements. Annualized non-market
benefits total $112.8 million per year
over 30 years (2022$, 3% discount rate).
The EPA’s monetary estimation of
benefits does not account for benefits
related to protections for a critically
endangered species (Atlantic Sturgeon),
increased housing values, or increased
commercial fishing, among other
benefits. Therefore, the EPA’s
estimation of non-market benefits is
likely an underestimate of total benefits
and thus total benefits could potentially
equal or exceed estimated total costs.
X. Statutory and Executive Order
Reviews
A. Executive Order 12866: Regulatory
Planning and Review and Executive
Order 14094: Modernizing Regulatory
Review
This action is not a significant
regulatory action as defined in
Executive Order 12866, as amended by
Executive Order 14094, and was
therefore not subject to a requirement
for Executive Order 12866 review.
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B. Paperwork Reduction Act (PRA)
This action does not impose any new
information collection burden under the
PRA. OMB has previously approved the
information collection activities
contained in the existing regulations
and has assigned OMB control number
2040–0049. While actions to implement
these WQS, if finalized, could entail
additional paperwork burden, this
action does not directly contain any
information collection, reporting, or
record-keeping requirements.
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C. Regulatory Flexibility Act (RFA)
I certify that this action will not have
a significant economic impact on a
substantial number of small entities
under the RFA. This action will not
impose any requirements on small
entities. Small entities, such as small
businesses or small governmental
jurisdictions, are not directly regulated
by this rulemaking.
EPA-promulgated WQS are
implemented through various water
quality control programs including the
NPDES program, which limits
discharges to navigable waters, except
in compliance with a NPDES permit.
CWA section 301(b)(1)(C) and the EPA’s
implementing regulations at 40 CFR
122.44(d)(1) and 122.44(d)(1)(A) provide
that all NPDES permits must include
any limits on discharges that are
necessary to meet applicable WQS.
Thus, under the CWA, the EPA’s
promulgation of WQS establishes
standards that states implement through
the NPDES permit process. While states
have discretion in developing discharge
limits, those limits ‘‘must control all
pollutants or pollutant parameters
(either conventional, nonconventional,
or toxic pollutants) which the Director
determines are or may be discharged at
a level that will cause, have the
reasonable potential to cause, or
contribute to an excursion above any
[s]tate water quality standard, including
[s]tate narrative criteria for water
quality’’ (40 CFR 122.44(d)(1)(i)).
As a result of this action, if finalized,
the states of Delaware, New Jersey, and
Pennsylvania will need to ensure that
permits they issue include any
limitations on discharges necessary to
comply with the WQS established in the
final rule. In doing so, each state will
have several choices associated with
permit writing. While each state’s
implementation of the rule may
ultimately result in new or revised
permit conditions for some dischargers,
including small entities, the EPA’s
action, by itself, does not impose any of
these requirements on small entities; in
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other words, these requirements are not
self-implementing.
D. Unfunded Mandates Reform Act
(UMRA)
This action does not contain any
unfunded mandate as described in
UMRA, 2 U.S.C. 1531–1538, and does
not significantly or uniquely affect small
governments. The action imposes no
enforceable duty on any state, local, or
Tribal governments or the private sector.
E. Executive Order 13132: Federalism
The EPA has concluded that this
action does not have federalism
implications. It will not have substantial
direct effects on the states, on the
relationship between the national
government and the states, or on the
distribution of power and
responsibilities among the various
levels of government. This rulemaking
would not alter Delaware’s, New
Jersey’s, or Pennsylvania’s considerable
discretion in implementing these WQS,
nor would it preclude any of those
states from adopting revised WQS and
submitting them to the EPA for review
and approval either before or after
promulgation of the final rule. If the
states submit and the EPA approves
revised WQS consistent with the CWA,
then the EPA would no longer be
required to promulgate Federal WQS.
Consistent with the EPA’s policy to
promote communications between the
EPA and state and local governments,
the EPA met with the states of Delaware,
New Jersey, and Pennsylvania and
DRBC in the process of developing this
rulemaking to enable them to have
meaningful input into its development.
During these discussions, the EPA
explained the scientific basis for the
dissolved oxygen criteria to protect
aquatic life propagation in the specified
zones of the Delaware River and the
overall timing of the Federal rulemaking
effort. The EPA took these discussions
with the states into account during the
drafting of this rulemaking. The EPA
specifically solicits comments on this
proposed action from state and local
officials.
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
This action does not have Tribal
implications as specified in Executive
Order 13175. This rulemaking will not
affect federally recognized Indian tribes
in Delaware, New Jersey, or
Pennsylvania because the WQS would
not apply to waters in Indian lands nor
affect Tribal interests. Thus, Executive
Order 13175 does not apply to this
action.
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G. Executive Order 13045: Protection of
Children From Environmental Health
and Safety Risks
The EPA interprets Executive Order
13045 as applying only to those
regulatory actions considered significant
under section 3(f)(1) of Executive Order
12866 and that concern environmental
health or safety risks that the EPA has
reason to believe may
disproportionately affect children, per
the definition of ‘‘covered regulatory
action’’ in section 2–202 of the
Executive order. Therefore, this action is
not subject to Executive Order 13045
because it does not concern an
environmental health risk or safety risk.
Since this action does not concern
human health, the EPA’s Policy on
Children’s Health also does not apply.
H. Executive Order 13211: Actions That
Significantly Affect Energy Supply,
Distribution, or Use
This action is not a ‘‘significant
energy action’’ because it is not likely to
have a significant adverse effect on the
supply, distribution, or use of energy.
This action proposes to establish
Federal CWA aquatic life water quality
criteria for specified zones of the
Delaware River under the jurisdiction of
the states of Delaware, New Jersey, and
Pennsylvania.
I. National Technology Transfer and
Advancement Act (NTTAA)
This rulemaking does not involve
technical standards.
J. Executive Order 12898: Federal
Actions To Address Environmental
Justice in Minority Populations and
Low-Income Populations and Executive
Order 14096: Revitalizing Our Nation’s
Commitment to Environmental Justice
for All
The information supporting this
Executive order review is summarized
below and detailed in the associated
document, Environmental Justice
Analysis for the Proposed Rule: Water
Quality Standards to Protect Aquatic
Life in the Delaware River, which is
available in the docket for this proposed
rule.
The EPA believes that the human
health or environmental conditions that
exist prior to this proposed action result
in or have the potential to result in
disproportionate and adverse human
health or environmental effects on
communities with environmental justice
(EJ) concerns. For this EJ analysis, the
EPA evaluated socioeconomic
characteristics of communities living
near the relevant zones of the Delaware
River compared to communities living
near other zones of the mainstem
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Delaware River. The relevant zones of
the Delaware River border highly
urbanized areas, including cities such as
Philadelphia and Wilmington.
Accordingly, the EPA’s analysis
accounts for the distinction between
urban and rural communities.89
The EPA obtained data from the
United States Census Bureau’s
American Community Survey (ACS) 5year estimates for the years 2017–2021
at the Census block group level to
construct a set of eight metrics for use
in this analysis: (1) Black or African
American, (2) Asian, (3) Two or More
Races, (4) Hispanic or Latino, (5)
Limited English Speaking Household,
(6) Median Household Income, (7)
Below 200% of the Poverty Level, (8)
Education Less than a High School
Diploma or Equivalent.90 Analysis of
these eight socioeconomic metrics
provides insight into the spatial
distribution and prevalence of certain
indicators of social vulnerability for
communities near the Delaware River.91
The EPA extended a five-mile buffer
from the specified zones to capture
communities living in close proximity
to waters affected by the EPA’s
proposed rule, if finalized.92 Similarly,
89 For this analysis, the EPA defines ‘‘urban’’ and
‘‘rural’’ using the Census Urban Areas designation.
More information about the Census classifications
is available at https://www.census.gov/programssurveys/geography/guidance/geo-areas/urbanrural.html.
90 The EPA also considered populations who
identify as American Indian and Alaskan Native,
Native Hawaiian and Other Pacific Islander, and
Some Other Race; however, in the Delaware River
watershed, these populations represent a very small
fraction (often less than 1%) of the community
composition. Therefore, these populations are not
analyzed further in this EJ analysis.
91 In the 2016 Technical Guidance for Assessing
Environmental Justice in Regulatory Analysis, the
EPA defined vulnerability as the ‘‘physical,
chemical, biological, social, and cultural factors that
result in certain communities and population
groups being more susceptible or more exposed to
environmental toxins, or having compromised
ability to cope with and/or recover from such
exposure.’’ For this EJ analysis, the EPA focused on
social vulnerability based on the metrics presented
in table 3 of the associated environmental justice
analysis, which broadly cover categories of race,
ethnicity, linguistic isolation, income, poverty, and
education. These metrics provide insight into
factors that may affect the ability of communities
near the Delaware River to respond to
environmental hazards or cope with reduced
ecosystem services that may result from inadequate
water quality. Although these socioeconomic
metrics are relevant to communities living near the
Delaware River, they are not intended to be an
exhaustive list of all factors affecting community
vulnerability. (Source: United States Environmental
Protection Agency. (2016). Technical Guidance for
Assessing Environmental Justice in Regulatory
Analysis. https://www.epa.gov/sites/default/files/
2016-06/documents/ejtg_5_6_16_v5.1.pdf.)
92 The EPA assumes that those living in Census
block groups that are within the five-mile buffer,
and therefore closest to the specified zones of the
Delaware River, are most likely to be directly
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the EPA extended a five-mile buffer
from other zones of the Delaware River
to form a comparison group. Given the
large number of block groups located
near the mainstem Delaware River,
communities are analyzed in groups, as
follows:
• Delaware Urban Areas: Census
block groups in urban areas within five
miles of the specified zones in
Delaware.
• New Jersey Urban Areas: Census
block groups in urban areas within five
miles of the specified zones in New
Jersey.
• Pennsylvania Urban Areas: Census
block groups in urban areas within five
miles of the specified zones in
Pennsylvania.
• Urban Comparison Group: Census
block groups in urban areas within five
miles of the remainder of the mainstem
Delaware River (i.e., excluding block
groups within five miles of the specified
zones).
• Specified Zones Rural Areas:
Census block groups in rural areas
within five miles of the specified zones
in New Jersey.93
• Rural Comparison Group: Census
block groups in rural areas within five
miles of the remainder of the mainstem
Delaware River (i.e., excluding block
groups within five miles of the specified
zones).
The EPA aggregated data across
multiple block groups using aerial
apportionment and a populationweighted mean approach to ensure that
block groups with larger or smaller
populations were accounted for
proportionally to their size. This
calculation relies on an assumption that
households are evenly distributed
within each block group. For Median
Household Income, the EPA aggregated
data across multiple block groups using
a linear interpolation calculation.
The results of the urban and rural
proximity analyses differed
significantly. Urban communities in
Pennsylvania near the specified zones
surpassed the comparison group average
(or were less than the comparison group
for Median Household Income) for all
eight socioeconomic metrics. Notably,
urban communities in Pennsylvania
near the specified zones are over 1.7
times more likely to identify as Black or
affected by the proposed rule. However, this
assumption could underestimate directly affected
communities and impact the results of the
proximity analysis. Accordingly, the EPA
conducted a sensitivity analysis using a ten-mile
buffer and determined that community composition
was not particularly sensitive to the buffer distance
applied when comparing the results of the five-mile
and ten-mile buffer.
93 There are no rural areas within five miles of the
specified zones in Delaware or Pennsylvania.
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African American, 1.7 times more likely
to live below twice the poverty level,
and have $23,000 lower median
household income when compared to
urban communities near the remainder
of the mainstem river. Urban
communities within five miles of the
specified zones in all three states had
lower income and higher poverty rates
than the comparison group. Urban
communities in Delaware near the
specified zones also had a higher
percentage of the population identify as
Black or African American than the
comparison group, while urban
communities in New Jersey had a higher
percentage of the population that
identifies as Hispanic or Latino and a
greater percentage with education less
than a high school degree than the
comparison group. Therefore, urban
communities near the specified zones—
especially in Pennsylvania—exhibited
differences in socioeconomic
community characteristics compared to
other urban communities near the
Delaware River.
On the other hand, rural communities
near the specified zones did not greatly
differ from rural communities near other
parts of the mainstem river. While rural
communities near the specified zones
did exceed the comparison group
average for four metrics (Black or
African American, Asian, Two or More
Races, and Limited English Speaking
Household), the differences were always
less than three percentage points.
Therefore, the EPA could not conclude
that rural communities near the
specified zones were any more or less
socially vulnerable compared to other
rural communities near the mainstem
Delaware River.
While neither the urban nor the rural
proximity analyses directly indicate
which communities may be
experiencing potential EJ concerns, they
provide insight into community
composition surrounding an
environmental resource. In general, the
Delaware River has had two contrasting
areas of water quality for decades. In the
relevant zones, water quality for aquatic
life has been significantly worse than in
the other zones of the river.94 Urban
areas near these zones, especially in
Pennsylvania, contain communities that
are likely more socially vulnerable than
urban communities that live near other
zones of the Delaware River, which have
better water quality. This trend in water
quality and dissolved oxygen across the
watershed, coupled with the
corresponding differences in
socioeconomic community composition,
reveals a potential inequitable
94 Delaware
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distribution of an environmental
resource and access to clean surface
waters within a single watershed.95
The EPA believes that this action
would be likely to reduce existing
disproportionate and adverse effects on
communities with EJ concerns.
Specifically, the EPA identified an
inequitable distribution of an
environmental resource where
communities with environmental justice
concerns have inequitable access to
clean surface waters that support CWA
section 101(a)(2) goals for aquatic life.
The EPA’s proposed rule, if finalized
and implemented, could help to lessen
this inequitable distribution of an
environmental resource by ensuring that
WQS to protect aquatic life in the
specified zones of the Delaware River
meet the objectives of the CWA.
In addition to the proximity analysis,
the EPA evaluated the potential
distribution of costs associated with the
proposed rule under the
implementation (policy) scenario
described in section IX of this preamble
and further detailed in the EPA’s
associated document, Economic
Analysis for the Proposed Rule: Water
Quality Standards to Protect Aquatic
Life in the Delaware River. For this
analysis, the EPA selected Philadelphia
as a case study based on the results of
the proximity analysis and the large
share of total estimated costs potentially
incurred by the Philadelphia Water
Department (PWD) compared to other
WWTPs.
The EPA used two methods to assess
the potential financial impact to
Philadelphia households resulting from
costs associated with the proposed rule.
First, the EPA calculated household
burden by quantifying the potential
increase to consumer water and
wastewater bills and calculating the
percentage of median household income
spent on water bills with and without
costs from additional wastewater
treatment plant controls. Second, the
EPA examined existing water rate
structures in Philadelphia and customer
assistance programs to identify possible
ways in which the affected
municipalities could adjust rates to
lessen the financial burden on lowincome households.
To determine household burden, the
EPA analyzed how annual water and
wastewater bills might change if costs
associated with additional wastewater
treatment plant controls at PWD
facilities are passed on to households
95 In this analysis, the EPA is not implying
causality between poor water quality and
socioeconomic factors.
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through increased water bills.96 The
EPA analyzed the financial impact to
households if costs were passed on to
residential households in proportion to
the estimated wastewater flow
attributed to residential households.97
DRBC estimates that approximately 15%
of the flow to PWD is attributable to
residential sources while 85% is
attributable to non-residential sources.98
Therefore, the EPA calculated
household burden assuming 15% of the
costs associated with additional
wastewater treatment plant controls
would be spread evenly among
Philadelphia households. Under this
assumption the additional annual cost
per household is $18.07, which would
equate to $1.50 per household per
month.99 For this analysis, the EPA
analyzed household burden using the
Residential Indicator in the EPA’s 2023
Clean Water Act Financial Capability
Assessment Guidance 100 and
determined that while the costs
associated with the proposed rule are
not expected to substantially impact
household burden under this scenario,
water bills still have the potential to be
placing a high burden on a third of
Philadelphia’s households. However,
the actual financial burden faced by
households depends on many factors,
including customer assistance programs.
In July 2017, Philadelphia became the
first to implement an income-based
alternative water rate structure through
creation of the Tiered Assistance
Program (TAP). This program is
structured based on household income
relative to the Federal poverty level
96 Residents in PWD’s service area pay a single
bill that covers both water and wastewater charges;
for this analysis, the EPA uses the term ‘‘water bill’’
to refer to the single bill covering water and
wastewater charges.
97 The EPA also analyzed a conservative scenario
in which 100% of costs are passed on to residential
households. Results of this scenario are available in
the associated document, Environmental Justice
Analysis for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware
River.
98 Delaware River Basin Commission. (2022c).
Social and Economic Factors Affecting the
Attainment of Aquatic Life Uses in the Delaware
River Estuary. September 2022 Draft. https://
www.nj.gov/drbc/library/documents/
AnalysisAttainability/SocialandEconomicFactors_
DRAFTsept2022.pdf.
99 As of September 1, 2023, the monthly water bill
for a typical residential consumer in Philadelphia
is $74.81, which equates to $897.72 annually.
Source: Philadelphia Water Department. Rate
Changes Effective September 2023. Web page,
accessed September 26, 2023. https://
water.phila.gov/drops/new-rate-informationeffective-september-2023/.
100 United States Environmental Protection
Agency. (2023). Clean Water Act Financial
Capability Assessment Guidance. Document ID:
800b21001. February 2023. https://www.epa.gov/
system/files/documents/2023-01/cwa-financialcapability-assessment-guidance.pdf.
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such that monthly bills are capped at
2%, 2.5%, 3%, and 4% of monthly
income for consumers whose income is
0–50%, >50–100%, >100–150%, and
>150% of the Federal poverty level,
respectively.101 TAP discounts are offset
by a surcharge added to the water bill
of non-TAP customers.
For illustrative purposes, the EPA
analyzed how the TAP rate structure
might apply to eligible low-income
consumers with water bills that include
15% of the costs associated with
additional PWD wastewater treatment
plant controls.102 Under the TAP rate
structure, a three-person household
with income at or below the poverty
level would have annual savings of at
least $294. These savings are
particularly significant for households
whose income is half the poverty level
or below. For example, a household at
50% of the poverty level would see
savings of $667.
However, the effectiveness of the TAP
rate structure depends in large part on
participation by eligible households.
When Philadelphia launched TAP in
2017, it was estimated that around
60,000 consumers would be eligible for
the program.103 However, as of
December 2022, only 14,712 households
were actively participating in TAP.104
Equally problematic as low
participation rates are the high attrition
rates of TAP participants. In 2022, 9,496
participants defaulted from TAP due to
a failure to recertify for the program. Of
those who defaulted, 75% percent did
not respond to the city’s request for
recertification.105 Thus, even though
Philadelphia enrolled 10,405
participants in 2022, the high attrition
rate in the program prevents meaningful
increases in participation. Philadelphia
continues outreach efforts to raise
awareness about TAP; 106 however, this
large gap in participation indicates that
101 City of Philadelphia. (2023). Annual Report to
the Mayor on the Tiered Assistance Program (TAP).
Department of Revenue. March 31, 2023. https://
www.phila.gov/media/20230526113411/TieredAssistance-Program-TAP-2022-annual-report.pdf.
102 The EPA does not have the necessary data to
calculate a per household surcharge that could
increase water bills for higher-income customers,
nor did the EPA include other assistance programs
in this calculation.
103 City of Philadelphia. (2017). Philadelphia
Launches New, Income-Based, Tiered Assistance
Program. Press Release. Office of the Mayor. June
20, 2017. https://www.phila.gov/press-releases/
mayor/philadelphia-launches-new-income-basedtiered-assistance-program/.
104 City of Philadelphia. (2023). Annual Report to
the Mayor on the Tiered Assistance Program (TAP).
Department of Revenue. March 31, 2023. https://
www.phila.gov/media/20230526113411/TieredAssistance-Program-TAP-2022-annual-report.pdf.
105 Id.
106 Id.
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the full potential of the program is likely
not being realized.
Based on the structure of TAP and the
current low participation rates, lowincome communities are not necessarily
protected from high water bills and
increasing water rates. The way the
program is designed, non-TAP
customers subsidize the discounts
applied to TAP customers. When there
is high participation, the majority of
program costs are borne by higher
income households and participating
low-income households are protected
from high water bills and increasing
water rates (including potential rate
increases to offset costs associated with
additional wastewater treatment plant
technologies). With low-participation
rates, a higher proportion of low-income
households are paying the TAP
surcharge and face higher water rates,
thus placing an undue burden on lowincome households not participating in
the program.
In theory, costs associated with the
EPA’s proposed rule—if partially or
fully passed on to residential
consumers—should not impact the
lowest income households in
Philadelphia, assuming high
participation in TAP. However, the
current low participation rates in TAP
indicate that some low-income
communities are likely burdened by
high water bills and could potentially
indirectly bear costs associated with the
EPA’s proposed rule. Although
Philadelphia’s TAP is innovative,
additional work to increase
participation (through increased
enrollment and decreased attrition rates)
can further advance water affordability
and protect low-income households.
The example of Philadelphia’s TAP
illustrates how an income-based rate
structure can potentially have a
measurable impact on low-income
communities. Municipalities potentially
affected by the EPA’s proposed rule
might consider holistic ways to advance
water affordability, which can include
adoption of alternative water rate
structures and assistance programs that
lower water bills for low-income
households. There are several
considerations for municipalities if
choosing to implement a program
similar to TAP in Philadelphia.107 An
income-based rate structure, such as
Philadelphia’s TAP, might be most
effective for utilities with larger service
areas and higher income disparities for
households within the service area.
When a utility has a large customer
base, it allows the utility to distribute
any surcharges (to offset lost revenue)
among many households.108 In theory,
this redistribution of costs means that
the per household surcharge can be
small and affect higher income
households who might be less socially
vulnerable. In addition, the
effectiveness of an income-based rate
structure hinges on the participation
rate of low-income communities.
Municipalities seeking to implement a
similar program should consider
practices to encourage high enrollment
and high retention rates among qualified
households. Such practices could
include automatically enrolling
households who are concurrently on
other assistance programs (such as
SNAP) or ensuring a user-friendly
process for recertification of eligibility,
if applicable. By thoughtfully and
strategically advancing water
affordability programs, municipalities
can work towards ensuring that socially
vulnerable communities are not
overburdened by expensive water bills.
List of Subjects in 40 CFR Part 131
Environmental protection, Indianslands, Intergovernmental relations,
Reporting and recordkeeping
requirements, Water pollution control.
Michael S. Regan,
Administrator.
For the reasons set forth in the
preamble, the EPA proposes to amend
40 CFR part 131 as follows:
PART 131—WATER QUALITY
STANDARDS
1. The authority citation for part 131
continues to read as follows:
■
Authority: 33 U.S.C. 1251 et seq.
■
2. Add § 131.XX to read as follows:
§ 131.XX Water quality standards to
protect aquatic life in the Delaware River.
(a) Scope. (1) The designated use in
paragraph (b) of this section applies to
river miles 108.4 to 70.0 of the Delaware
River for the states of New Jersey and
Pennsylvania.
(2) The aquatic life criteria in
paragraph (c) of this section apply to
river miles 108.4 to 70.0 of the Delaware
River for the states of Delaware, New
Jersey, and Pennsylvania.
(b) Aquatic life designated use. The
aquatic life designated use is protection
and propagation of resident and
migratory aquatic life.
(c) Dissolved oxygen criteria. The
applicable dissolved oxygen criteria are
shown in table 1 to this paragraph (c).
TABLE 1 TO PARAGRAPH (c)—DISSOLVED OXYGEN CRITERIA
Magnitude
(percent oxygen
saturation)
Season
Spawning and Larval Development (March 1–June 30) ...................
Juvenile Development (July 1–October 31) ......................................
66
66
74
66
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Overwintering (November 1–February 28/29) ...................................
Duration
Daily
Daily
Daily
Daily
Average
Average
Average
Average
(d) Applicability. (1) The aquatic life
designated use in paragraph (b) of this
section applies concurrently with other
applicable designated uses in New
Jersey and Pennsylvania for river miles
108.4 to 70.0 of the Delaware River.
(2) The dissolved oxygen aquatic life
water quality criteria in paragraph (c) of
this section are the applicable dissolved
oxygen criteria in Delaware, New Jersey,
and Pennsylvania for river miles 108.4
to 70.0 of the Delaware River and apply
concurrently with applicable water
quality criteria for other parameters.
(3) The designated use and criteria
established are subject to Delaware’s,
107 Mack, E.A., Wrase, S., Dahme, J., Crosby, S.M.,
Davis, M., Wright, M., & Muhammad, R. (2020). An
Experiment in Making Water Affordable:
Philadelphia’s Tiered Assistance Program (TAP).
Journal of the American Water Resources
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Exceedance frequency
........
........
........
........
10%
10%
50%
10%
(12
(12
(61
(12
Days
Days
Days
Days
Cumulative).
Cumulative).
Cumulative).
Cumulative).
New Jersey’s, and Pennsylvania’s
general rules of applicability in the
same way and to the same extent as are
other federally promulgated and stateadopted water quality standards in
those states.
[FR Doc. 2023–27758 Filed 12–20–23; 8:45 am]
BILLING CODE 6560–50–P
Association, 56(3), 431–449. https://doi.org/
10.1111/1752-1688.12830.
108 Id.
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]]>Agencies
[Federal Register Volume 88, Number 244 (Thursday, December 21, 2023)]
[Proposed Rules]
[Pages 88315-88336]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-27758]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 131
[EPA-HQ-OW-2023-0222; FRL 10760-01-OW]
RIN 2040-AG30
Water Quality Standards To Protect Aquatic Life in the Delaware
River
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: On December 1, 2022, the U.S. Environmental Protection Agency
(EPA) determined that revised water quality standards are necessary to
protect aquatic life in certain water quality management zones of the
Delaware River. Specifically, the EPA issued an Administrator's
Determination, pursuant to the Clean Water Act (CWA), finding that a
revised designated use to protect aquatic life propagation and
corresponding dissolved oxygen criteria to protect that use are
necessary in Zone 3, Zone 4, and the upper portion of Zone 5 (in total,
river miles 108.4 to 70.0) of the Delaware River. The CWA requires the
EPA to publish proposed water quality standards following an
Administrator's Determination. Thus, the EPA is proposing to promulgate
an aquatic life designated use that includes propagation and protective
water quality criteria for dissolved oxygen for Zone 3, Zone 4, and
upper Zone 5 of the Delaware River.
DATES: Comments must be received on or before February 20, 2024. Public
hearing: the EPA will hold two public hearings during the public
comment period. Please refer to the SUPPLEMENTARY INFORMATION section
for additional information on the public hearings.
ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OW-2023-0222, by any of the following methods:
Federal eRulemaking Portal: https://www.regulations.gov/
(our preferred method). Follow the online instructions for submitting
comments.
Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Office of Water Docket, Mail Code 28221T, 1200 Pennsylvania
Avenue NW, Washington, DC 20460.
Hand Delivery or Courier: EPA Docket Center, WJC West
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004.
The Docket Center's hours of operations are 8:30 a.m.-4:30 p.m., Monday
through Friday (except Federal holidays).
Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received may be posted without change
to https://www.regulations.gov/, including any personal information
provided. For detailed instructions on sending comments and additional
information on the rulemaking process, see the ``Public Participation''
heading of the SUPPLEMENTARY INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Hannah Lesch, Office of Water,
Standards and Health Protection Division (4305T), Environmental
Protection Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460;
telephone number: (202) 566-1224; email address: [email protected].
SUPPLEMENTARY INFORMATION: This proposed rule preamble is organized as
follows:
I. Public Participation
A. Written Comments
B. Participation in Public Hearings
II. General Information
[[Page 88316]]
A. Does this action apply to me?
III. Background
A. Statutory and Regulatory Authority
B. Relevant Ecological History of the Delaware River
C. Administration of Water Quality Standards in the Delaware
River
D. Currently Applicable Aquatic Life Designated Uses and
Dissolved Oxygen Criteria
E. Summary of the EPA's Administrator's Determination
IV. Proposed Water Quality Standards
A. Scope of EPA's Proposed Rule
B. Proposed Aquatic Life Designated Use
C. Dissolved Oxygen Criteria To Protect Aquatic Life Propagation
V. Endangered Species Act Consultation
VI. Applicability
VII. Conditions Where Federal Water Quality Standards Would Not Be
Promulgated or Would Be Withdrawn
A. Conditions Where Federal Standards Would Not Be Promulgated
B. Conditions Where Federal Standards Would Be Withdrawn
VIII. Alternative Regulatory Approaches and Implementation
Mechanisms
A. Water Quality Standards Variances
B. NPDES Permit Compliance Schedules
C. Clean Water Act Section 303(d)/305(b) Water Quality
Assessments
IX. Economic Analysis
X. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 14094: Modernizing Regulatory Review
B. Paperwork Reduction Act (PRA)
C. Regulatory Flexibility Act (RFA)
D. Unfunded Mandates Reform Act (UMRA)
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045: Protection of Children From
Environmental Health and Safety Risks
H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act (NTTAA)
J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations and Executive Order 14096: Revitalizing Our Nation's
Commitment to Environmental Justice for All
I. Public Participation
A. Written Comments
Submit your comments, identified by Docket ID No. EPA-HQ-OW-2023-
0222, at https://www.regulations.gov (the EPA's preferred method), or
the other methods identified in the ADDRESSES section. Once submitted,
comments cannot be edited or removed from the docket. The EPA may
publish any comment received to its public docket. Do not submit to the
EPA's docket at https://www.regulations.gov any information you
consider to be Confidential Business Information (CBI), Proprietary
Business Information (PBI), or other information whose disclosure is
restricted by statute. Multimedia submissions (audio, video, etc.) must
be accompanied by a written comment. The written comment is considered
the official comment and should include discussion of all points you
wish to make. The EPA will generally not consider comments or comment
contents located outside of the primary submission (i.e., on the web,
cloud, or other file sharing system). Please visit https://www.epa.gov/dockets/commenting-epa-dockets for additional submission methods; the
full EPA public comment policy; information about CBI, PBI, or
multimedia submissions; and general guidance on making effective
comments.
B. Participation in Public Hearings
The EPA is offering two public hearings so that interested parties
may also provide oral comments on this proposed rulemaking. For more
details on the public hearings and to register to attend the hearings,
please visit https://www.epa.gov/wqs-tech/water-quality-standards-delaware-river.
II. General Information
A. Does this action apply to me?
A range of individuals and entities could be affected by this
rulemaking, if finalized. For example, entities that discharge
pollutants to certain waters under the jurisdiction of the states of
Delaware, New Jersey, and Pennsylvania--such as industrial facilities
and municipalities that manage stormwater, separate sanitary, or
combined sewer systems--could be indirectly affected by this rulemaking
because Federal water quality standards (WQS) promulgated by the EPA
would be the applicable WQS for these waters for CWA purposes (Table 1
of this preamble). Specifically, these WQS would be the applicable
standards that must be used in CWA regulatory programs, such as
permitting under the National Pollutant Discharge Elimination System
(NPDES) under CWA section 402 \1\ and identifying impaired waters under
CWA section 303(d). In addition, individuals and entities who rely on
or benefit from aquatic life in those waters may be indirectly
affected.
---------------------------------------------------------------------------
\1\ Before any water quality-based effluent limit would be
included in an NPDES permit, the permitting authority (here, the
states of Delaware, New Jersey, and Pennsylvania), must first
determine whether a discharge ``will cause or has the reasonable
potential to cause, or contribute to an excursion above any WQS.''
40 CFR 122.44(d)(1)(i) and (ii).
Table 1--Entities Potentially Affected by This Proposed Rule
------------------------------------------------------------------------
Examples of potentially affected
Category entities
------------------------------------------------------------------------
Industry.......................... Industrial point sources discharging
to certain waters in Delaware, New
Jersey, and Pennsylvania.
Commercial fishing operations that
harvest fish.
Municipalities, including those Publicly owned treatment works or
with stormwater or combined sewer similar facilities responsible for
system outfalls. managing stormwater, separate
sanitary, or combined sewer systems
that discharge to certain waters in
Delaware, New Jersey, and
Pennsylvania.
Recreation and Tourism............ Anglers and tourists seeking
recreational opportunities related
to aquatic life in certain waters
in Delaware, New Jersey, and
Pennsylvania.
------------------------------------------------------------------------
This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities that could be indirectly affected
by this action. If you have questions regarding the applicability of
this action to a particular entity, consult the person listed in the
FOR FURTHER INFORMATION CONTACT section above.
III. Background
A. Statutory and Regulatory Authority
CWA section 101(a)(2) establishes a national goal of ``water
quality which provides for the protection and propagation of fish,
shellfish, and wildlife, and provides for recreation in and on the
water'' (hereafter, collectively referred to as ``101(a)(2) uses'' or
``101(a)(2) goals''), wherever attainable. The EPA's regulation at 40
CFR 131.10(g) implements this statutory
[[Page 88317]]
provision by requiring that WQS protect 101(a)(2) uses unless those
uses are shown to be unattainable.
Under the CWA, states have the primary responsibility for
reviewing, establishing, and revising WQS applicable to their waters
(CWA section 303(c)). WQS define the desired condition of a water body,
in part, by designating the use or uses to be made of the water and by
setting the numeric or narrative water quality criteria to protect
those uses (40 CFR 131.2, 131.10, and 131.11). There are two primary
categories of water quality criteria: human health criteria and aquatic
life criteria. Human health criteria protect designated uses such as
public water supply, recreation, and fish and shellfish consumption.
Aquatic life criteria protect designated uses such as protection and
propagation of fish, invertebrates, and other aquatic species.
Regardless of their category, water quality criteria ``must be based on
sound scientific rationale and must contain sufficient parameters or
constituents to protect the designated use. For waters with multiple
use designations, the criteria shall support the most sensitive use''
(40 CFR 131.11(a)(1)).
States are required to hold a public hearing to review applicable
WQS at least once every three years and, if appropriate, revise or
adopt new standards (CWA section 303(c)(1); 40 CFR 131.20(a)). Every
three years, states must also reexamine water body segments that do not
include the 101(a)(2) uses to determine if new information has become
available that indicates the 101(a)(2) uses are attainable, and if so,
revise the WQS accordingly (40 CFR 131.20(a)). Any new or revised WQS
must be submitted to the EPA for review and approval or disapproval
(CWA section 303(c)(2)(A) and (c)(3)).
CWA section 303(c)(4)(B) independently authorizes the Administrator
to determine that a new or revised standard is necessary to meet CWA
requirements; this action is frequently referred to as an
``Administrator's Determination.'' Pursuant to CWA section
303(c)(4)(B), after making an Administrator's Determination, the EPA
must propose and promulgate WQS specified in the Administrator's
Determination. If a state adopts and the EPA approves WQS that address
the Administrator's Determination prior to the EPA's promulgation, then
the EPA would no longer be required to promulgate WQS.
B. Relevant Ecological History of the Delaware River
The Delaware River has historically been home to numerous species
of ecological, recreational, and economic importance; however,
centuries of anthropogenic water quality impacts and habitat
degradation, peaking in the mid-twentieth century, made portions of the
river unsuitable for many aquatic species. In the 1700s and 1800s, many
native fish species in the Delaware River faced declining populations
due to overharvesting and the installation of physical barriers that
prevented fish passage.\2\ Further population declines of native
oxygen-sensitive species--such as the Atlantic Sturgeon (Acipenser
oxyrinchus oxyrinchus), American Shad (Alosa sapidissima), Shortnose
Sturgeon (Acipenser brevirostrum), and Striped Bass (Morone saxatilis),
among others \3\--were linked to accelerating degradation of water
quality through the first half of the 1900s, including seasonal anoxia
(i.e., absence of oxygen) by the mid-twentieth century in Zone 3, Zone
4, and the upper portion of Zone 5 of the Delaware River.\4\
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\2\ Hardy, C.A. (1999). Fish or Foul: A History of the Delaware
River Basin Through the Perspective of the American Shad, 1682 to
the Present. Pennsylvania History, 66(4), 506-534. https://digitalcommons.wcupa.edu/hist_facpub/13; Secor, D.H. and Waldman, J.
(1999). Historical abundance of Delaware Bay Atlantic sturgeon and
potential rate of recovery. American Fisheries Society Symposium.
23. 203-216. https://www.researchgate.net/publication/291783957_Historical_abundance_of_Delaware_Bay_Atlantic_sturgeon_and_potential_rate_of_recovery; Smith, T.I.J., & Clugston, J.P. (1997)
Status and management of Atlantic sturgeon, Acipenser oxyrinchus, in
North America. Environmental Biology of Fishes 48, 335-346. https://doi.org/10.1023/A:1007307507468; National Marine Fisheries Service.
(1998). Recovery Plan for the Shortnose Sturgeon (Acipenser
brevirostrum). Prepared by the Shortnose Sturgeon Recovery Team for
the National Marine Fisheries Service, Silver Spring, Maryland. 104
pages. https://repository.library.noaa.gov/view/noaa/15971.
\3\ Stoklosa, A.M., Keller, D.H., Marano, R., and Horwitz, R.J.
(2018). ``A Review of Dissolved Oxygen Requirements for Key
Sensitive Species in the Delaware Estuary.'' Academy of Natural
Sciences of Drexel University. November 2018. https://www.nj.gov/drbc/library/documents/Review_DOreq_KeySensSpecies_DelEstuary_ANStoDRBCnov2018.pdf.
\4\ See citations in footnote 2 of this preamble; Atlantic
States Marine Fisheries Commission. (1981). Interstate Fisheries
Management Plan for the Striped Bass. https://www.asmfc.org/uploads/file/1981FMP.pdf.
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Dissolved oxygen is an important water quality parameter that can
significantly influence the distribution and abundance of aquatic
organisms and ecological relationships in aquatic ecosystems. Aquatic
organisms need to obtain adequate levels of dissolved oxygen to
maintain and support normal functioning, including during sensitive
life stages, such as spawning, larval development, and juvenile
growth.\5\ As dissolved oxygen levels decrease in a waterbody, the rate
at which aquatic organisms can obtain oxygen from the water decreases,
resulting in impaired growth and reduced survival. Maintaining a
healthy ecosystem requires dissolved oxygen levels above thresholds
that impair growth and survival of aquatic species.
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\5\ United States Environmental Protection Agency. (2021).
Factsheet on Water Quality Parameters: Dissolved Oxygen. July 2021.
Document ID: EPA 841F21007B. https://www.epa.gov/system/files/documents/2021-07/parameter-factsheet_do.pdf; United States
Environmental Protection Agency. (2023a). Indicators: Dissolved
Oxygen. June 9, 2023. https://www.epa.gov/national-aquatic-resource-surveys/indicators-dissolved-oxygen.
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1. Causes of Low Dissolved Oxygen in the Specified Zones of the
Delaware River
Discharges of untreated or poorly treated municipal and industrial
wastewater into the specified zones of the Delaware River have
historically been a major cause of water quality degradation, including
oxygen depletion.\6\ While conditions have significantly improved,
inputs of oxygen-consuming wastes from wastewater dischargers,
especially ammonia (NH3) and ammonium (NH4\+\)
(which in combination are hereafter referred to as ``ammonia
nitrogen''), as well as sediment-water ammonium flux and sediment
oxygen demand continue to be significant sources of oxygen demand in
the specified zones of the Delaware River.\7\
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\6\ Hardy (1999); Delaware River Basin Commission. (2022a).
Analysis of Attainability: Improving Dissolved Oxygen and Aquatic
Life Uses in the Delaware River Estuary. September 2022 Draft. See
section 3--``Factors that can Improve Dissolved Oxygen in the Fish
Maintenance Area.'' https://www.nj.gov/drbc/library/documents/AnalysisAttainability/AnalysisAttainability_DRAFTsept2022.pdf.
\7\ Delaware River Basin Commission. (2022b). Modeling
Eutrophication Processes in the Delaware River Estuary--Three-
Dimensional Water Quality Model. https://www.nj.gov/drbc/library/documents/AnalysisAttainability/WQModelCalibrationRpt_DRAFTsept2022.pdf.
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Along the Delaware River, untreated wastewater discharges typically
occur during and after rainfall due to combined sewer overflows (CSOs),
which are a source of nutrients (i.e., nitrogen and phosphorus),
sediments, and toxic contaminants, and can lead to increased chemical
and biological oxygen demand in the river.\8\ Although the cumulative
impact of historical
[[Page 88318]]
CSOs on sediment oxygen demand in the Delaware River has not been
estimated, CSOs can over time increase or maintain sediment oxygen
demand as untreated organic material settles on the riverbed and is
broken down by oxygen consuming bacteria (thus, removing oxygen from
the water column), a process that continues long after the end of an
overflow event.\9\ CSOs have been a persistent source of pollutants in
the specified zones of the Delaware River for over a century. For
example, sewer overflows from Philadelphia in the early 1900s deposited
over 200,000 tons of solids per year, which, in combination with other
solid wastes, created deposits 12 feet deep in the river.\10\ From July
1, 2021, to June 30, 2022, Philadelphia's wastewater system alone
discharged over 1.7 billion cubic feet of CSOs into the Delaware
River.\11\
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\8\ Miskewitz, R. and Uchrin, C. (2013). In-Stream Dissolved
Oxygen Impacts and Sediment Oxygen Demand Resulting from Combined
Sewer Overflow Discharges. Journal of Environmental Engineering,
139(10). https://doi.org/10.1061/(ASCE)EE.1943-7870.0000739.
\9\ Miskewitz and Uchrin (2013).
\10\ Hardy (1999).
\11\ Philadelphia Water Department. (2022). Combined Sewer
Management Program Annual Report. Stormwater Management Program
Annual Report. See Appendix D--``NPDES Annual CSO Status Report FY
2022,'' Table 2--``Overflow Summary for 7/1/2021-6/30/2022.''
https://water.phila.gov/pool/files/fy22-npdes-annual-report.pdf.
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Although most point source discharges today are treated, treated
effluent can still contain high levels of ammonia nitrogen, which
depletes oxygen in the water as bacteria oxidize ammonia into nitrite,
nitrate and dinitrogen gas.\12\ During the reporting periods from July
through October 2022, major wastewater treatment facilities along the
Delaware River discharged ammonia nitrogen at monthly average
concentrations ranging from a low of 0.07 milligrams nitrogen per liter
(mg-N/L) at the Florence Township Sewage Treatment Plant in New Jersey
(discharging into Zone 2 of the Delaware River) to a high of 35 mg-N/L
at the Camden County Municipal Utilities Authority in New Jersey
(discharging into Zone 3 of the Delaware River).\13\
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\12\ United States Environmental Protection Agency. (2023b).
Ammonia. https://www.epa.gov/caddis-vol2/ammonia.
\13\ Each individual reporting period is one month long. For the
reporting period ending on September 30, 2022, Florence Township
Municipal Building discharged an average of .07 mg/L of ammonia. For
the reporting period ending on July 31, 2022, Camden County
Municipal Utilities Authority discharged an average of 35 mg/L of
ammonia. Source: U.S. Environmental Protection Agency. Integrated
Compliance Information System (ICIS). Database. Retrieved June 29,
2023.
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2. Endangered Species in the Specified Zones of the Delaware River
The Delaware River is home to two oxygen-sensitive fish species--
Shortnose Sturgeon and Atlantic Sturgeon--that are protected under the
Federal Endangered Species Act (ESA). All populations of Shortnose
Sturgeon were listed as endangered in 1967.\14\ Across the U.S.,
Shortnose Sturgeon face ongoing threats due to water pollution, habitat
degradation, and fisheries bycatch, among other factors.\15\ While the
historic population size of Shortnose Sturgeon in the Delaware River
remains unknown, in 2006 the population was estimated to be
approximately 12,000 adults.\16\ The New York Bight distinct population
segment (DPS) of Atlantic Sturgeon--which includes the population found
in the Delaware River--was listed as endangered under the ESA in
2012.\17\ In 2017, the National Oceanic and Atmospheric Administration
(NOAA Fisheries) designated the Delaware River, among others, as
critical habitat for the New York Bight DPS of Atlantic Sturgeon,\18\
and reaffirmed its endangered listing in 2022 following a five-year
review of its status.\19\ The remnant population of the New York Bight
DPS of Atlantic Sturgeon faces ongoing threats due to water quality in
natal rivers, such as the Delaware River, as well as climate change,
ship strikes, fisheries bycatch, habitat loss, and entanglement in
fishing gear.20 21 Like the Shortnose Sturgeon, the historic
population size of Atlantic Sturgeon is not well documented. However,
in 1890, when the population was already declining, there were
approximately 180,000 female Atlantic Sturgeon in the Delaware
River.\22\ Despite improvements in dissolved oxygen levels since the
1970s, it is estimated that only 125-250 adult Atlantic Sturgeon
currently return to spawn in the Delaware River.\23\
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\14\ Federal Register, Vol. 32, No. 48 (32 FR 4000). March 11,
1967. https://www.fisheries.noaa.gov/s3//2022-12/4000-4002.pdf.
\15\ NOAA Fisheries. (2023a). Shortnose Sturgeon--Overview.
https://www.fisheries.noaa.gov/species/shortnose-sturgeon.
\16\ Id.; NOAA Fisheries. (2023b). Shortnose Sturgeon--
Populations. https://www.fisheries.noaa.gov/species/shortnose-sturgeon#populations.
\17\ Federal Register, Vol. 77, No. 24. February 6, 2012. 77 FR
5879. https://www.federalregister.gov/documents/2012/02/06/2012-1946/endangered-and-threatened-wildlife-and-plants-threatened-and-endangered-status-for-distinct.
\18\ Federal Register, Vol. 82, No. 158 (82 FR 39160). August
17, 2017. 50 CFR part 226. https://www.federalregister.gov/documents/2017/08/17/2017-17207/endangered-and-threatened-species-designation-of-critical-habitat-for-the-endangered-new-york-bight.
\19\ National Marine Fisheries Service. (2022). New York Bight
Distinct Population Segment of Atlantic Sturgeon (Acipenser
oxyrinchus oxyrinchus), 5-Year Review: Summary and Evaluation.
February 17, 2022. https://www.fisheries.noaa.gov/resource/document/new-york-bight-distinct-population-segment-atlantic-sturgeon-5-year-review.
\20\ Ibid. See Section 2.3.2, ``Five-Factor Analysis (threats,
conservation measures, and regulatory mechanisms)'', A. through E.,
pp. 14-25.
\21\ Dunton, K.J., Jordaan, A., Conover, D.O., McKown, K.A.,
Bonacci, L.A., and Frisk, M.G. (2015). Marine Distribution and
Habitat Use of Atlantic Sturgeon in New York Lead to Fisheries
Interactions and Bycatch. Marine and Coastal Fisheries 7:18-32.
https://doi.org/10.1080/19425120.2014.986348; Atlantic Sturgeon
Bycatch Working Group. (2022). Action Plan to Reduce Atlantic
Sturgeon Bycatch in Federal Large Mesh Gillnet Fisheries. NOAA
National Marine Fisheries Service. https://media.fisheries.noaa.gov/2022-09/Final-Action-Plan-to-Reduce-Atlantic-Sturgeon-Bycatch.pdf.
\22\ Secor and Waldman (1999).
\23\ White, S.L., Sard, N.M., Brundage, H.M., Johnson, R.L.,
Lubinski, B.A., Eackles, M.S., Park, I.A., Fox, D.A., and Kazyak,
D.C. (2022). Evaluating Sources of Bias in Pedigree-Based Estimates
of Breeding Population Size. Ecological Applications 32(5): e2602.
https://doi.org/10.1002/eap.2602.
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In addition to being listed as endangered under the ESA, available
evidence suggests that Shortnose Sturgeon and Atlantic Sturgeon are the
most oxygen-sensitive species in the specified zones of the Delaware
River. In general, all sturgeon species share common life history
traits,\24\ among which they are recognized to be relatively more
sensitive to low dissolved oxygen levels compared to other co-occurring
fish.25 26 Sturgeons are considered unusually sensitive to
hypoxia given their documented metabolic and behavioral responses and
limited ability to oxyregulate.\27\ Juvenile Atlantic Sturgeon are
particularly sensitive to low dissolved oxygen levels, especially at
high water temperatures,\28\ such as those typically present at the
peak of summer in the Delaware River.\29\ A literature review across
oxygen-
[[Page 88319]]
sensitive species in the Delaware River indicates that Atlantic
Sturgeon, particularly the juvenile life stage, have the highest
documented dissolved oxygen requirements for growth and survival when
compared to other oxygen-sensitive species in the specified zones of
the Delaware River.\30\ In its five-year review of the listing of the
New York Bight DPS of Atlantic Sturgeon, NOAA Fisheries observed a
continuation of low dissolved oxygen conditions in the Delaware River
around the expected location of age 0-1 Atlantic Sturgeon.\31\ Low
oxygen levels can lead to habitat displacement effects whereby juvenile
Atlantic Sturgeon seeking relief are constrained to waters that remain
suboptimal for growth due to other limiting factors (e.g., higher
salinity waters).\32\ NOAA Fisheries also noted studies linking age 0-1
Atlantic Sturgeon capture rates in the fall to the preceding summer
dissolved oxygen conditions in the Delaware River, providing further
evidence that low dissolved oxygen levels are a contributor to the
mortality of juvenile Atlantic Sturgeon.\33\
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\24\ Federal Register, Vol. 82, No. 158 (82 FR 39161). August
17, 2017. 50 CFR part 226. pp. 39161-39163. https://www.federalregister.gov/documents/2017/08/17/2017-17207/endangered-and-threatened-species-designation-of-critical-habitat-for-the-endangered-new-york-bight.
\25\ Ibid. p. 39162, see Dees (1961), Sulak and Clugston (1999),
Billard and Lecointre (2001), Secor and Niklitschek (2002), and
Pikitch et al. (2005), cited therein.
\26\ Stoklosa et al. (2018) ; Secor, D.H. and Niklitschek, E.J.
(2001). Hypoxia and Sturgeons: Report to the Chesapeake Bay Program
Dissolved Oxygen Criteria Team. March 29, 2001.Reference Number:
[UMCES] CBL 01-0080. https://www.researchgate.net/publication/277065759_Hypoxia_and_Sturgeons_report_to_the_Chesapeake_Bay_Program_Dissolved_Oxygen_Criteria_Team.
\27\ Secor and Niklitschek (2001). Oxyregulation refers to an
organism's ability to maintain metabolic rates as the oxygen level
in the water declines.
\28\ Secor, D., and T. Gunderson. (1998). Effects of hypoxia and
temperature on survival, growth, and respiration of juvenile
Atlantic sturgeon, Acipenser oxyrinchus. Fishery Bulletin 96:603-
613.; Niklitschek, E. (2001). Bioenergetics modeling and assessment
of suitable habitat for juvenile Atlantic and shortnose sturgeons
(Acipenser oxyrinchus and A. brevirostrum) in the Chesapeake Bay.
University of Maryland at College Park.
\29\ More information is available in the associated document,
Technical Support Document for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware River.
\30\ Stoklosa et al. (2018).
\31\ National Marine Fisheries Service (2022). See Section
2.3.2.1, ``Present or threatened destruction, modification, or
curtailment of its habitat or range.''
\32\ Ibid. See Allen et al. (2014), cited therein.
\33\ Ibid. See Moberg and DeLucia (2016), Stetzar et al. (2015),
and Park (2020), cited therein.
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3. Dissolved Oxygen Trends in the Specified Zones of the Delaware River
Dissolved oxygen levels in Zone 3, Zone 4, and the upper portion of
Zone 5 of the Delaware River mirror trends in historic pollutant
loading and recent pollution control efforts in the river. Average
summer dissolved oxygen levels in the Delaware River near Chester,
Pennsylvania (Zone 4) declined from near saturation in the late 1880s
to near zero (i.e., anoxia) in the 1950s and 1960s.\34\ Starting in
1970, dissolved oxygen levels began to increase steadily in association
with declining ammonia nitrogen concentrations in the river.\35\
Reductions in nutrient concentrations, including ammonia nitrogen, have
been documented across the Delaware River watershed through at least
2018.\36\ However, dissolved oxygen levels in the summer remain low
enough to limit the growth and survival of oxygen-sensitive species and
life stages, such as juvenile Atlantic Sturgeon.\37\ Recent modeling
studies have shown that further reductions in pollutant loading,
including a reduction in the volume and frequency of CSOs as well as
enhanced treatment of ammonia nitrogen discharges, could significantly
improve the dissolved oxygen conditions in the relevant zones of the
Delaware River.\38\
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\34\ Sharp, J. (2010). Estuarine oxygen dynamics: What can we
learn about hypoxia from long-time records in the Delaware estuary?
Limnology and Oceanography, 55(2), 535-548.
\35\ Sharp (2010).
\36\ Shoda, M.E., and Murphy, J.C. (2022). Water-quality trends
in the Delaware River Basin calculated using multisource data and
two methods for trend periods ending in 2018. U.S. Geological Survey
Scientific Investigations Report 2022-5097. https://doi.org/10.3133/sir20225097.
\37\ More information is available in the associated document,
Technical Support Document for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware River; Delaware
River Basin Commission (2022a); Niklitschek, E., and D. Secor.
(2009a). Dissolved oxygen, temperature and salinity effects on the
ecophysiology and survival of juvenile Atlantic sturgeon in
estuarine waters: I. Laboratory results. Journal of Experimental
Marine Biology and Ecology 381:S150-S160. https://doi.org/10.1016/j.jembe.2009.07.018; Stoklosa et al. (2018).
\38\ Delaware River Basin Commission (2022a, 2022b).
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C. Administration of Water Quality Standards in the Delaware River
In 1961, the Delaware River Basin Compact established the Delaware
River Basin Commission (DRBC), comprised of the states of Delaware, New
Jersey, New York,\39\ and Pennsylvania and the Federal Government, to
jointly manage the Delaware River Basin's water resources.\40\ Through
DRBC, each state participates in the shared governance of this regional
resource and maintains sovereign rights over the portion of the river
within its jurisdiction.\41\
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\39\ Although portions of the Delaware River Estuary are within
New York's jurisdiction, the EPA's proposed rulemaking is not
applicable to waters under New York's jurisdiction (see section
IV.A. of this preamble: Scope of EPA's Proposed Rule). Therefore,
the EPA does not discuss New York's WQS further in this proposed
rulemaking.
\40\ DRBC was established pursuant to Federal law (75 Stat. 688
(1961)).
\41\ Delaware River Basin Compact, art. 1, ``Short Title,
Definitions, Purpose and Limitations,'' Sec. 1.3(a), (b), & (c)
``Purpose and Findings,'' pp. 3 & 4, and art. 5, ``Pollution
Control,'' Sec. 5.5(b), ``Further Jurisdiction,'' p. 11, (1961),
available at https://www.nj.gov/drbc/library/documents/compact.pdf.
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Pursuant to the Delaware River Basin Compact, DRBC adopts WQS for
interstate waters, including the Delaware River Estuary.\42\ However as
noted above, under the CWA, states have the primary responsibility for
reviewing, establishing, and revising WQS applicable to their waters,
and must submit new or revised WQS to the EPA for review and approval
or disapproval.
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\42\ Delaware River Basin Compact, art. 5, ``Pollution
Control,'' Sec. 5.2, ``Policy and Standards,'' p. 11 (1961),
available at https://www.nj.gov/drbc/library/documents/compact.pdf
(DRBC ``may adopt and from time to time amend and repeal rules,
regulations and standards to control . . . future pollution and
abate existing pollution''). DRBC, the states, and the EPA refer to
these rules, regulations, and standards as equivalent to WQS under
the CWA. As such, the term WQS is used herein to refer to these
rules, regulations, and standards.
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Given the unique interjurisdictional management of the Delaware
River Estuary, WQS are submitted to the EPA for review through a
process coordinated across the state, regional, and Federal levels.
This process begins when DRBC adopts WQS for the Delaware River
Estuary. To comply with CWA section 303(c), the Estuary states of
Delaware, New Jersey, and Pennsylvania have provisions in their state
WQS regulations that explicitly reference or implicitly incorporate
DRBC's WQS as the applicable WQS for the portions of the river under
their jurisdictions. When DRBC adopts new or revised WQS, each relevant
member state submits a certification to the EPA from that state's
attorney general or other appropriate legal authority, in accordance
with 40 CFR 131.6(e). Those certifications provide that DRBC's new or
revised WQS were duly adopted pursuant to state law. The EPA then
reviews whether those WQS are consistent with the CWA and the EPA's
implementing regulation and approves or disapproves them.
D. Currently Applicable Aquatic Life Designated Uses and Dissolved
Oxygen Criteria
In 1967, DRBC adopted WQS for the zones of the Delaware River
included in this proposed rule.\43\ Based on the conditions of the
Delaware River at the time, DRBC concluded that ``propagation of fish''
was not attainable for Zone 3, Zone 4, and the upper portion of Zone 5
(in total, river miles 108.4 to 70.0) of the Delaware River (hereafter,
referred to as ``specified zones'' or ``relevant zones''),\44\ due to
the presence of industrial and municipal discharges and associated low
dissolved oxygen levels. DRBC, therefore, adopted WQS to include
``maintenance of resident fish and other aquatic life,'' ``passage of
anadromous fish,'' and a dissolved oxygen criterion of 3.5 mg/L, as a
daily average, for these
[[Page 88320]]
zones of the Delaware River.45 46 Because these WQS provide
for the ``maintenance'' and ``passage'' of aquatic life (i.e.,
``protection'') but not the ``propagation of fish, shellfish and
wildlife,'' these WQS are not consistent with the goals specified in
CWA section 101(a)(2). However, these WQS adopted in 1967 remain
applicable for Zone 3, Zone 4, and the upper portion of Zone 5 of the
Delaware River as directly referred to or implicitly incorporated in
Delaware's, New Jersey's, and Pennsylvania's WQS.
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\43\ Delaware River Basin Commission. (2013). Delaware River
Basin Water Code. https://www.nj.gov/drbc/library/documents/watercode.pdf.
\44\ A map showing the Delaware River watershed and the
specified zones is available in the docket (Docket ID No. EPA-HQ-OW-
2023-0222) as well as in each of the support documents associated
with this rule: Technical Support Document for the Proposed Rule:
Water Quality Standards to Protect Aquatic Life in the Delaware
River; Economic Analysis for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware River; and
Environmental Justice Analysis for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware River.
\45\ Delaware River Basin Commission. (2015). ``Existing Use
Evaluation for Zones 3, 4, & 5 of the Delaware Estuary Based on
Spawning and Rearing of Resident and Anadromous Fishes.'' September
30, 2015. https://www.state.nj.us/drbc/library/documents/ExistingUseRpt_zones3-5_sept2015.pdf.
\46\ Anadromous fish are species that are born and reared as
juveniles in freshwater, migrate to marine waters where they spend
most of their adult lives, and return to their natal, freshwater
rivers to spawn.
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1. Delaware's, New Jersey's, and Pennsylvania's Current Aquatic Life
Designated Uses
As described in section III.C. of this preamble, Delaware, New
Jersey, and Pennsylvania each has its own WQS for the specified zones
of the Delaware River under its jurisdiction. Delaware's current
aquatic life designated use for the specified zones of the Delaware
River includes all life stages, thus including the propagation
component of the CWA section 101(a)(2) use. New Jersey's aquatic life
designated use for the specified zones of the Delaware River
incorporate by reference the designated uses in DRBC's Water Quality
Regulations. Pennsylvania's aquatic life designated uses for the
specified zones of the Delaware River align with DRBC's ``maintenance''
and ``passage'' designated use (Table 2 of this preamble). Therefore,
neither New Jersey's nor Pennsylvania's aquatic life designated use for
the specified zones of the Delaware River include the propagation
component of the CWA section 101(a)(2) use.
Table 2--Current Aquatic Life Designated Uses in Zone 3, Zone 4, and
Upper-Zone 5 of the Delaware River
------------------------------------------------------------------------
Entity Designated use
------------------------------------------------------------------------
DRBC \1\........................ Maintenance of resident fish and other
aquatic life, passage of anadromous
fish, wildlife.
Delaware \2\.................... Fish, Aquatic Life & Wildlife.\3\
New Jersey \4\.................. The designated uses for the mainstem
Delaware River and Delaware Bay are
those contained in the DRBC Water
Quality Regulations.
Pennsylvania \5\................ Warm Water Fishes (Maintenance Only);
Migratory fishes (Passage Only).\6\
------------------------------------------------------------------------
\1\ Delaware River Basin Commission. ``Administrative Manual--Part III
Water Quality Regulations with Amendments Through December 7, 2022.''
Accessed May 3, 2023. https://www.nj.gov/drbc/library/documents/WQregs.pdf.
\2\ Delaware Administrative Code. ``7401 Surface Water Quality
Standards.'' Title 7 Natural Resources & Environmental Control.
Delaware Department of Natural Resource and Environmental Control.
Accessed May 3, 2023. https://regulations.delaware.gov/AdminCode/title7/7000/7400/7401.pdf.
\3\ Delaware defines Fish, Aquatic Life & Wildlife as, ``all animal and
plant life found in Delaware, either indigenous or migratory,
regardless of life stage or economic importance.'' A footnote
specifies that this use includes shellfish propagation.
\4\ New Jersey Administrative Code. ``N. J. A. C. 7:9B Surface Water
Quality Standards.'' Accessed May 3, 2023. https://dep.nj.gov/wp-content/uploads/rules/rules/njac7_9b.pdf.
\5\ Pennsylvania Code. ``Chapter 93. Water Quality Standards.''
Commonwealth of Pennsylvania. Accessed May 3, 2023. https://www.pacodeandbulletin.gov/secure/pacode/data/025/chapter93/025_0093.pdf.
\6\ Pennsylvania defines its ``Warm Water Fishes'' designated use as,
``Maintenance and propagation of fish species and additional flora and
fauna which are indigenous to a warm water habitat'' and defines its
``Migratory Fishes'' designated use as, ``Passage, maintenance and
propagation of anadromous and catadromous fishes and other fishes
which move to or from flowing waters to complete their life cycle in
other waters.'' For the specified zones of the Delaware River,
Pennsylvania excluded propagation from the designated uses by
specifying ``Maintenance Only'' and ``Passage Only'' in parentheses.
2. Delaware's, New Jersey's, and Pennsylvania's Current Dissolved
Oxygen Criteria
For dissolved oxygen in the relevant zones, all three states
incorporate DRBC's water quality criteria by reference; therefore,
DRBC's dissolved oxygen criteria are the applicable criteria for the
relevant zones in each state (Table 3 of this preamble). As explained
above with respect to the aquatic life designated use, DRBC's dissolved
oxygen criteria for the specified zones of the Delaware River do not
protect for aquatic life propagation and are therefore not consistent
with CWA section 101(a)(2) goals.
Table 3--Current Dissolved Oxygen Criteria in Zone 3, Zone 4, and Upper-
Zone 5 of the Delaware River
------------------------------------------------------------------------
Entity Dissolved oxygen aquatic life criteria
------------------------------------------------------------------------
DRBC \1\........................ 24-hour average concentration shall
not be less than 3.5 mg/l. During the
periods from April 1 to June 15, and
September 16 to December 31, the
dissolved oxygen shall not have a
seasonal average less than 6.5 mg/l
in the entire zone.
Delaware \2\.................... For waters of the Delaware River and
Delaware Bay, duly adopted Delaware
River Basin Commission (DRBC) Water
Quality Regulations shall be the
applicable criteria.
New Jersey \3\.................. For parameters with criteria in the
DRBC Water Quality Regulations, the
criteria contained therein are the
applicable criteria.
Pennsylvania \4\................ See DRBC Water Quality Regulations.
------------------------------------------------------------------------
\1\ Delaware River Basin Commission. ``Administrative Manual--Part III
Water Quality Regulations with Amendments Through December 7, 2022.''
Accessed May 3, 2023. https://www.nj.gov/drbc/library/documents/WQregs.pdf.
\2\ Delaware Administrative Code. ``7401 Surface Water Quality
Standards.'' Title 7 Natural Resources & Environmental Control.
Delaware Department of Natural Resource and Environmental Control.
Accessed May 3, 2023. https://regulations.delaware.gov/AdminCode/title7/7000/7400/7401.pdf.
\3\ New Jersey Administrative Code. ``N. J. A. C. 7:9B Surface Water
Quality Standards.'' Accessed May 3, 2023. https://dep.nj.gov/wp-content/uploads/rules/rules/njac7_9b.pdf.
\4\ Pennsylvania Code. ``Chapter 93. Water Quality Standards.''
Commonwealth of Pennsylvania. Accessed May 3, 2023. https://www.pacodeandbulletin.gov/secure/pacode/data/025/chapter93/025_0093.pdf.
[[Page 88321]]
3. Intersection of Delaware's, New Jersey's, and Pennsylvania's Current
Aquatic Life Designated Uses and Dissolved Oxygen Criteria With CWA
101(a)(2) Goals
Table 4 of this preamble provides a summary outlining whether
Delaware's, New Jersey's, and Pennsylvania's current aquatic life
designated uses align with CWA section 101(a)(2) goals and whether each
state's current dissolved oxygen criteria are protective of an aquatic
life designated use that includes propagation. As explained above,
Delaware is the only state that includes aquatic life propagation in
its designated uses for the specified zones of the Delaware River.
However, none of the three states' dissolved oxygen water quality
criteria for the specified zones are protective of fish and shellfish
propagation. Therefore, none of the states, and by extension none of
the specified zones of the Delaware River, currently has a set of WQS
for aquatic life that are fully consistent with the CWA section
101(a)(2) goals (i.e., ``water quality which provides for the
protection and propagation of fish, shellfish, and wildlife [. . .]'').
Table 4--Intersection of Delaware's, New Jersey's, and Pennsylvania's Current Aquatic Life Designated Uses and
Dissolved Oxygen Criteria With CWA 101(a)(2) Goals
----------------------------------------------------------------------------------------------------------------
Dissolved oxygen
Designated use includes criteria protective of
State Applicable zone(s) CWA section 101(a)(2) aquatic life
propagation component propagation
----------------------------------------------------------------------------------------------------------------
Delaware............................. Upper-5................ Yes.................... No.
New Jersey........................... 3, 4, Upper-5.......... No..................... No.
Pennsylvania......................... 3, 4................... No..................... No.
----------------------------------------------------------------------------------------------------------------
E. Summary of the EPA's Administrator's Determination
On December 1, 2022, the EPA determined that the CWA section
101(a)(2) use of propagation is now attainable and therefore revised
WQS are necessary to protect aquatic life in certain water quality
management zones of the Delaware River.\47\ Specifically, the EPA
issued an Administrator's Determination, pursuant to CWA section
303(c)(4)(B), finding that a revised designated use to protect aquatic
life propagation and corresponding dissolved oxygen criteria to protect
that use are necessary in Zone 3, Zone 4, and the upper portion of Zone
5 (in total, river miles 108.4 to 70.0) of the Delaware River. The
Administrator's Determination can be accessed at https://www.epa.gov/wqs-tech/federally-promulgated-water-quality-standards-specific-states-territories-and-tribes.
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\47\ December 1, 2022. Letter from Radhika Fox, Assistant
Administrator, EPA Office of Water, to Steven J. Tambini, Executive
Director, Delaware River Basin Commission; Shawn M. Garvin,
Secretary, Delaware Department of Natural Resources and
Environmental Control; Shawn M. LaTourette, Commissioner, New Jersey
Department of Environmental Protection; and Ramez Ziadeh, Acting
Secretary, Pennsylvania Department of Environmental Protection.
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IV. Proposed Water Quality Standards
A. Scope of EPA's Proposed Rule
In accordance with the Administrator's Determination, the EPA's
proposed rule, if finalized, would apply to Zone 3, Zone 4, and the
upper portion of Zone 5 of the Delaware River (in total, river miles
108.4 to 70.0), for the states of Delaware, New Jersey, and
Pennsylvania (Table 5 of this preamble).
Table 5--Zones of the Delaware River Covered by the EPA's Proposed Rule
------------------------------------------------------------------------
Segment of the Delaware River River miles States affected
------------------------------------------------------------------------
Zone 3.......................... 108.4 to 95.0..... New Jersey,
Pennsylvania.
Zone 4.......................... 95.0 to 78.8...... New Jersey,
Pennsylvania.
Zone 5--Upper Portion........... 78.8 to 70.0...... Delaware, New
Jersey.
------------------------------------------------------------------------
B. Proposed Aquatic Life Designated Use
The EPA is proposing to promulgate a revised aquatic life
designated use for the specified zones of the Delaware River to meet
the CWA section 101(a)(2) goals (i.e., ``water quality which provides
for the protection and propagation of fish, shellfish, and wildlife''),
as specified in the EPA's Administrator's Determination.\48\ Although
the relevant zones of the Delaware River are each under the
jurisdiction of two or more states (Table 5 of this preamble), CWA
section 303(c) assigns the individual states the role of adopting WQS.
Therefore, the EPA is evaluating the aquatic life uses on a state-by-
state basis.
---------------------------------------------------------------------------
\48\ The EPA's Administrator's Determination stated, ``EPA is
determining [. . . that] revised aquatic life designated uses that
provide for propagation of fish, consistent with CWA section
101(a)(2) and 40 CFR 131.20(a) [. . .] are necessary for zone 3,
zone 4, and the upper portion of zone 5 (in total, river miles 108.4
to 70.0) of the Delaware River Estuary, to meet the requirements of
the CWA.''
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As explained in section III.D. of this preamble, Delaware's ``Fish,
Aquatic Life & Wildlife'' designated use includes all life stages of
indigenous and migratory organisms; therefore, Delaware's aquatic life
designated use in the specified zones under its jurisdiction is already
consistent with the CWA section 101(a)(2) goals and no revisions to
Delaware's aquatic life designated use are necessary to meet CWA
requirements. In contrast, New Jersey's and Pennsylvania's aquatic life
designated uses for the relevant zones of the Delaware River under
their jurisdiction do not include ``propagation'' and are therefore not
consistent with CWA section 101(a)(2) goals. As explained in section
III.E. of this preamble, the EPA determined that propagation is now an
attainable use in the specified zones of the Delaware River.\49\
Therefore, for the portions of the specified zones under New Jersey's
and Pennsylvania's jurisdiction, a
[[Page 88322]]
revised aquatic life designated use that includes propagation is
necessary to meet CWA requirements and ensure that the specified zones
of the Delaware River are consistent with CWA section 101(a)(2) goals.
---------------------------------------------------------------------------
\49\ December 1, 2022. Letter from Radhika Fox, Assistant
Administrator, EPA Office of Water, to Steven J. Tambini, Executive
Director, Delaware River Basin Commission; Shawn M. Garvin,
Secretary, Delaware Department of Natural Resources and
Environmental Control; Shawn M. LaTourette, Commissioner, New Jersey
Department of Environmental Protection; and Ramez Ziadeh, Acting
Secretary, Pennsylvania Department of Environmental Protection.
---------------------------------------------------------------------------
Thus, the EPA is proposing to promulgate an aquatic life designated
use for Zone 3, Zone 4, and the upper portion of Zone 5 of the Delaware
River (in total, river miles 108.4 to 70.0) for the states of New
Jersey and Pennsylvania, as follows: Protection and propagation of
resident and migratory aquatic life.
C. Dissolved Oxygen Criteria To Protect Aquatic Life Propagation
The EPA is proposing to establish dissolved oxygen criteria--
derived from the latest sound scientific information--for Delaware, New
Jersey, and Pennsylvania, for the specified zones of the Delaware
River. The proposed dissolved oxygen criteria would protect the EPA's
proposed designated use for New Jersey and Pennsylvania, as well as
Delaware's current aquatic life designated use for the specified zones.
1. Derivation of Dissolved Oxygen Criteria
To derive protective dissolved oxygen criteria for the specified
zones of the Delaware River, the EPA used methods adapted from peer-
reviewed literature and data from laboratory studies relevant to
oxygen-sensitive sturgeon species in the Delaware River. Although the
methods and data are from peer-reviewed scientific literature, the EPA
is nonetheless in the process of completing an external peer review on
the application of these methods and data in this context where the EPA
is proposing criteria to protect proposed and applicable aquatic life
designated uses that include propagation. This section presents a
summary of the data and methods that the EPA used to derive protective
dissolved oxygen criteria for this proposed rulemaking. First, the EPA
describes the Agency's existing dissolved oxygen national
recommendations and guidance documents. Then, the EPA explains how the
Agency selected three seasons to derive criteria protective of oxygen-
sensitive species in the relevant zones of the Delaware River. Next,
the EPA details an Atlantic Sturgeon cohort model used to derive
criteria protective of juvenile Atlantic Sturgeon during the season
associated with their growth and development. After that, the EPA
explains how criteria were developed to protect oxygen-sensitive
species during the other two seasons. Lastly, the EPA concludes with an
explanation for proposing criteria expressed as percent oxygen
saturation, rather than as concentration. This section is intended to
be a high-level summary of the EPA's criteria derivation methods and
results for this proposed rulemaking. More details and information are
available in the associated technical support document, Technical
Support Document for the Proposed Rule: Water Quality Standards to
Protect Aquatic Life in the Delaware River. The EPA will consider
information received during the public comment period (detailed above),
in addition to the external peer review of the technical support
document, and accordingly may make changes to the proposed criteria for
a final rule.
Existing the EPA Methodology and Guidance Documents
Under CWA section 304(a), the EPA publishes, from time to time,
national recommended aquatic life criteria for a variety of pollutants
and parameters. The EPA's national recommended criteria for dissolved
oxygen in freshwater and saltwater environments are from the 1986
Quality Criteria for Water (``Gold Book'') \50\ and the 2000 Ambient
Aquatic Life Water Quality Criteria for Dissolved Oxygen (Saltwater):
Cape Cod to Cape Hatteras (``Virginian Province Document''),\51\
respectively. The EPA's recommendations in the Virginian Province
Document state that, ``in cases where a threatened or endangered
species occurs at a site, and sufficient data exist to suggest that it
is more sensitive at concentrations above the criteria, it is
appropriate to consider development of site-specific criteria based on
this species.'' \52\ As explained previously in section III.B. of this
preamble, Atlantic Sturgeon and Shortnose Sturgeon are federally listed
as endangered under the ESA and are uniquely sensitive to hypoxia.
Given the availability of laboratory data specific to the oxygen
requirements of Atlantic Sturgeon and Shortnose Sturgeon, the EPA chose
to derive site-specific criteria to protect the oxygen-sensitive
endangered species in the specified zones of the Delaware River and not
rely on the national recommendations in the Gold Book or Virginian
Province Document in this instance.
---------------------------------------------------------------------------
\50\ United States Environmental Protection Agency. (1986).
Quality Criteria for Water 1986. Document ID: EPA 440/5-86-001. May
1, 1986. https://www.epa.gov/sites/default/files/2018-10/documents/quality-criteria-water-1986.pdf.
\51\ United States Environmental Protection Agency. (2000).
Ambient Aquatic Life Water Quality Criteria for Dissolved Oxygen
(Saltwater): Cape Cod to Cape Hatteras. Document ID: EPA-822-R-00-
012. November 2000. https://www.epa.gov/sites/default/files/2018-10/documents/ambient-al-wqc-dissolved-oxygen-cape-code.pdf.
\52\ Id. Page 41.
---------------------------------------------------------------------------
Delineating Seasons for Criteria Derivation
In consideration of available information, including information
developed by DRBC, the EPA is proposing to delineate three distinct
seasons for dissolved oxygen criteria development that are intended to
protect Atlantic Sturgeon early life stages, while also protecting a
range of other aquatic species' sensitive life stages in the specified
zones. The EPA is proposing to define the Spawning and Larval
Development season as occurring from March 1 to June 30, which
generally covers spawning and egg and larval development periods for
many oxygen-sensitive species, including Atlantic Sturgeon, Shortnose
Sturgeon, American Shad, Atlantic Rock Crab, Channel Catfish, Striped
Bass, Largemouth Bass, White Perch, and Yellow Perch.\53\ The EPA is
proposing to define the Juvenile Development season as occurring from
July 1 to October 31 and the Overwintering season as occurring from
November 1 to February 28/29, based on young-of-the-year juvenile
Atlantic Sturgeon growth rates.\54\ By November, growth rates are
reduced by low water temperatures despite relatively high levels of
dissolved oxygen.\55\ While the EPA is proposing to define seasons
largely based on the early life stages of Atlantic Sturgeon, the
proposed seasons also generally correspond with early life stages of
other oxygen-sensitive species in the specified zones of the Delaware
River. By developing criteria that are protective of Atlantic Sturgeon,
which, as described in section III.B. of this preamble, is the most
oxygen-sensitive species in the relevant zones of the Delaware River,
the EPA concluded that the criteria would also be protective of other
less oxygen-sensitive resident and
[[Page 88323]]
migratory aquatic species in the specified zones of the Delaware River.
---------------------------------------------------------------------------
\53\ Stoklosa et al. (2018); Delaware River Basin Commission
(2015); Moberg, T. and M. DeLucia. (2016). Potential Impacts of
Dissolved Oxygen, Salinity and Flow on the Successful Recruitment of
Atlantic Sturgeon in the Delaware River. The Nature Conservancy.
Harrisburg, PA. https://www.conservationgateway.org/ConservationPractices/Freshwater/HabitatProtectionandRestoration/Documents/DelawareAtlanticSturgeonReport_TNC5172016.pdf.
\54\ Moberg and DeLucia. (2016).
\55\ This conclusion was based on results of the growth model,
described in sections 3.3.3 and 4.1.2 of the associated document,
Technical Support Document for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware River.
---------------------------------------------------------------------------
Ecological Modeling To Derive Criteria for the Juvenile Development
Season
The EPA obtained recent and high-quality data from a variety of
sources, described below and detailed in the associated technical
support document, to evaluate oxygen requirements of Atlantic Sturgeon
in each season. The EPA quantified water quality conditions in the
specified zones of the Delaware River using recent and high-quality
monitoring data from two locations in the Delaware River. Since the
Atlantic Sturgeon was listed as an endangered species in 2012, there
have been few recent studies documenting their oxygen requirements.
However, available data on sturgeon growth and mortality from Campbell
and Goodman (2004), Niklitschek and Secor (2009a), and EPA (2003),
along with methods from Niklitschek and Secor (2005) and Niklitschek
and Secor (2009b), water quality monitoring data, and juvenile Atlantic
Sturgeon abundance data from the Delaware Department of Natural
Resources and Environmental Control (DNREC) provided the EPA with
sufficient data to establish quantitative relationships between age-0
juvenile sturgeon growth, mortality, and habitat suitability.\56\
---------------------------------------------------------------------------
\56\ Campbell, J., and L. Goodman. (2004). Acute sensitivity of
juvenile shortnose sturgeon to low dissolved oxygen concentrations.
Transactions of the American Fisheries Society 133:722-776;
Niklitschek, E., and D. Secor. (2009a). Dissolved oxygen,
temperature and salinity effects on the ecophysiology and survival
of juvenile Atlantic sturgeon in estuarine waters: I. Laboratory
results. Journal of Experimental Marine Biology and Ecology
381:S150-S160. https://doi.org/10.1016/j.jembe.2009.07.018; United
States Environmental Protection Agency. (2003). Ambient Water
Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll
a for the Chesapeake Bay and its Tidal Tributaries. Document ID: EPA
903-R-03-002. April 2003. https://nepis.epa.gov/Exe/ZyPDF.cgi/P100YKPQ.PDF?Dockey=P100YKPQ.PDF; Niklitschek, E.J., and D.H. Secor.
(2005). Modeling spatial and temporal variation of suitable nursery
habitats for Atlantic sturgeon in the Chesapeake Bay. Estuarine,
Coastal and Shelf Science 64:135-148. https://doi.org/10.1016/j.ecss.2005.02.012; Niklitschek, E.J., and D.H. Secor. (2009b).
Dissolved oxygen, temperature and salinity effects on the
ecophysiology and survival of juvenile Atlantic sturgeon in
estuarine waters: II. Model development and testing. Journal of
Experimental Marine Biology and Ecology 381:S161-S172. https://doi.org/10.1016/j.jembe.2009.07.019; USGS 01467200 Delaware River at
Penn's Landing, Philadelphia, PA. Retrieved March 9, 2023. https://waterdata.usgs.gov/nwis/inventory/?site_no=01467200&agency_cd=USGS;
USGS 01477050 Delaware River at Chester PA. Retrieved January 31,
2023. https://waterdata.usgs.gov/nwis/inventory?agency_code=USGS&site_no=01477050; Park, I. (2023). State
of Delaware Annual Compliance Report for Atlantic Sturgeon. Delaware
Division of Fish and Wildlife, Department of Natural Resources and
Environmental Control. September 2023.
---------------------------------------------------------------------------
The EPA followed the peer-reviewed cohort modeling approach of
Niklitschek and Secor (2005) to evaluate the effects of temperature,
salinity, and dissolved oxygen on the potential growth and mortality of
a hypothetical cohort or group of juvenile Atlantic Sturgeon spawned
during a single year.\57\ The cohort model uses growth and mortality
rates to calculate the instantaneous daily production potential, or the
instantaneous amount of biomass produced per unit of cohort biomass per
day. The EPA used the cohort model to estimate the fraction of the
cohort that survives from July 1 through October 31 (i.e., the Juvenile
Development season) and the relative change in biomass for the same
period.
---------------------------------------------------------------------------
\57\ Water temperature and salinity can affect the oxygen
requirements of aquatic species and are needed to compute percent
oxygen saturation, a measure of dissolved oxygen availability to
aquatic organisms, from dissolved oxygen concentrations.
---------------------------------------------------------------------------
As part of the cohort model, the EPA developed a new mortality
model and implemented a peer-reviewed bioenergetics-based growth model
described by Niklitschek and Secor (2009b) to predict the daily
instantaneous mortality rate and growth rate, respectively, for members
of the cohort. To develop a mortality model, the EPA fit a regression
to experimental data to predict mortality resulting from low dissolved
oxygen at any given temperature and percent oxygen saturation.\58\
Mortality rates of juvenile sturgeons increased with declining
dissolved oxygen levels and increased at higher rates with both
declining dissolved oxygen and increasing water temperature. The EPA
validated the results of the mortality model by using observed water
quality data to predict relative abundance of the Atlantic Sturgeon
young-of-year cohort on October 31 and comparing those results to catch
data from DNREC's juvenile abundance surveys.\59\ The growth model
takes a bioenergetic approach that accounts for temperature-controlled
maximum metabolic rates that may be further limited by oxygen levels.
Low oxygen levels limit overall metabolic rates and cause a shift in
the allocation of available energy away from growth. Predicted growth
rates reflect the balance between energy inputs and losses and are
therefore reduced by low oxygen. Water quality monitoring data in the
relevant zones of the Delaware River show that the lowest oxygen levels
coincided with the highest water temperatures, resulting in lower
growth rates than either condition would cause alone.
---------------------------------------------------------------------------
\58\ Experimental data are from Campbell and Goodman 2004,
Niklitschek and Secor 2009a.
\59\ USGS 01467200 Delaware River at Penn's Landing,
Philadelphia, PA. Retrieved March 9, 2023. https://waterdata.usgs.gov/nwis/inventory/?site_no=01467200&agency_cd=USGS;
USGS 01477050 Delaware River at Chester, PA. Retrieved January 31,
2023. https://waterdata.usgs.gov/nwis/inventory?agency_code=USGS&site_no=01477050; Park (2023).
---------------------------------------------------------------------------
Habitat Suitability Indices have been used in the context of fish-
habitat relationships, conservation management, and habitat evaluation
to quantify the capacity of a given habitat to support essential life
functions (e.g., growth, survival, reproduction) of a selected
species.\60\ For this proposed rulemaking, the EPA defined a Habitat
Suitability Index (HSI) for Atlantic Sturgeon as the instantaneous
daily production potential, which was calculated using the cohort
model. HSI evaluates the combined effect of percent oxygen saturation,
water temperature, and salinity on the potential growth and survival of
juvenile Atlantic Sturgeon during the Juvenile Development season. The
EPA used quantile generalized additive models (QGAMs) to quantify
relationships between computed values of HSI in each year and
corresponding seasonal percentiles of daily dissolved oxygen for that
year.\61\ QGAMs can model the non-linear relationship between dissolved
oxygen and HSI as well as predict the expected median HSI, rather than
the expected mean.
---------------------------------------------------------------------------
\60\ E.g., Woodland, R.J., Secor, D.H., and Niklitschek, E.J.
(2009). Past and Future Habitat Suitability for the Hudson River
Population of Shortnose Sturgeon: A Bioenergetic Approach to
Modeling Habitat Suitability for an Endangered Species. American
Fisheries Society Symposium 69: 589-604; Collier, J.J., Chiotti,
J.A., Boase, J., Mayer, C.M., Vandergoot, C.S., and Bossenbroek,
J.M. (2022). Assessing habitat for lake sturgeon (Acipenser
fulvescens) reintroduction to the Maumee River, Ohio using habitat
suitability index models. Journal of Great Lakes Research. 48(1):
219-228. https://doi.org/10.1016/j.jglr.2021.11.006; Brown, S.K.,
Buja, K.R., Jury, S.H., Monaco, M.E., and Banner, A. (2000). Habitat
Suitability Index Models for Eight Fish and Invertebrate Species in
Casco and Sheepscot Bays, Maine. North American Journal of Fisheries
Management, 20(2): 408-435, https://doi.org/10.1577/1548-8675(2000)020%3C0408:HSIMFE%3E2.3.CO;2.
\61\ A percentile (e.g., 10th percentile) is the dissolved
oxygen level below which the corresponding fraction (e.g., 10%) of
the daily dissolved oxygen values during the season falls below. In
this case, the season is the Juvenile Development season (July 1-
October 31).
---------------------------------------------------------------------------
The EPA followed the approach of Niklitschek and Secor (2005) to
define suitable habitat for juvenile Atlantic Sturgeon growth and
survival as habitats with water quality resulting in HSI greater than
zero. When HSI is less than or equal to zero, seasonal average
mortality rates are greater than or equal to seasonal average growth
rates and the overall biomass of the cohort is likely to decrease.
Conversely, a cohort of
[[Page 88324]]
juveniles utilizing habitat with HSI greater than zero has the
potential to increase its biomass during the Juvenile Development
season, thus contributing to successful propagation. Therefore, to
derive protective dissolved oxygen criteria, the EPA evaluated seasonal
percentiles of percent oxygen saturation to find the lowest value at
which the QGAMs predict expected median HSI>0 as the minimum thresholds
for percent oxygen saturation that, if attained, would provide suitable
habitat during that seasonal period. The EPA requests comment on the
conclusion that HSI greater than zero defines suitable habitat for
juvenile Atlantic Sturgeon growth and survival, or alternatively, if
evidence could support that a value of HSI less than zero could also be
protective or if a higher HSI threshold may be needed to protect
propagation in the specified zones. Similarly, the EPA requests comment
on its use of QGAM to relate percentiles of dissolved oxygen levels to
the conditional median HSI. These models can be understood to find the
minimum dissolved oxygen level that if achieved would result in an
expectation that HSI would be equal to or greater than zero as often or
more often than if it is less than zero. As an alternative, the QGAM
could predict a lower conditional percentile, providing a high degree
of certainty that HSI would be greater than zero if the dissolved
oxygen level was attained. For example, at the dissolved oxygen level
where the expected 25th percentile HSI=0, HSI would be expected to
equal or exceed zero 75% of the time.
The predicted HSI value relies on an expected distribution of
percent oxygen saturation values during the season; therefore, the EPA
selected two percent oxygen saturation percentiles as thresholds at or
above which median HSI is expected to be greater than zero to maintain
the expected distribution of percent oxygen saturation values. These
two percentiles--the 10th percentile and the 50th percentile--describe
the protective seasonal distribution of dissolved oxygen values. When
both the 10th percentile and 50th percentile are attained, they
function together to ensure that a detrimental shift in the oxygen
distribution (i.e., a shift causing more low oxygen levels) at either
the low end (10th percentile) or the center (50th percentile) of the
dissolved oxygen distribution has not occurred. Median HSI is expected
to be zero or higher, allowing the annual cohort of juvenile Atlantic
Sturgeon to maintain or increase its biomass, when the 10th percentile
of oxygen saturation is at least 66% and the 50th percentile, or
median, of oxygen saturation is at least 74%. Therefore, the EPA
expects oxygen levels will not impair juvenile Atlantic Sturgeon during
the Juvenile Development season if the 10th percentile of oxygen
saturation is at least 66% and the 50th percentile of oxygen saturation
is at least 74%.
Criteria Development for Spawning and Larval Development and
Overwintering Seasons
The Atlantic Sturgeon cohort model described above relies on
experimental studies that were conducted using juvenile Atlantic
Sturgeon and therefore provide information that is most relevant to
juvenile growth and survival.\62\ Additionally, the underlying studies
allocated most experimental treatments to water temperatures between 12
[deg]C and 28 [deg]C, with only a single experimental treatment at 6
[deg]C and none at lower water temperatures.\63\ The EPA's cohort
modeling approach therefore does not apply to spawning and larval
development lifestages and has minimal relevance to the overwintering
period. Accordingly, the EPA did not use the cohort model to derive
criteria for the Spawning and Larval Development or the Overwintering
seasons.
---------------------------------------------------------------------------
\62\ Experimental data are from Campbell and Goodman 2004 and
Niklitschek and Secor 2009a.
\63\ Niklitschek and Secor 2009a.
---------------------------------------------------------------------------
Instead, the EPA concluded that Atlantic Sturgeon larvae were
likely to be as sensitive to low dissolved oxygen as juvenile Atlantic
Sturgeon \64\ and that overwintering juveniles have temperature-limited
metabolism and therefore have similar or slightly lower oxygen
requirements than juveniles in warmer waters (e.g., summer water
temperatures).\65\ Thus, the EPA determined that the percent oxygen
saturation threshold that would be protective of juveniles experiencing
stressful (high) water temperatures during the Juvenile Development
season would also be protective of larvae and overwintering juveniles
not experiencing high water temperatures. Therefore, the EPA expects
oxygen levels will not impair Atlantic Sturgeon when the 10th
percentile of oxygen saturation is at least 66% during the Spawning and
Larval Development and Overwintering seasons. The EPA notes that from
2002-2022, the median oxygen level during the Spawning and Larval
Development and Overwintering seasons was well above levels expected to
negatively impact either Atlantic Sturgeon or other oxygen-sensitive
species. Therefore, the EPA concluded that a second criterion for a
50th percentile was not needed during these seasons.
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\64\ Stoklosa et al. (2018); United States Environmental
Protection Agency. (2000). Ambient Aquatic Life Water Quality
Criteria for Dissolved Oxygen (Saltwater): Cape Cod to Cape
Hatteras. Document ID: EPA-822-R-00-012. November 2000. https://www.epa.gov/sites/default/files/2018-10/documents/ambient-al-wqc-dissolved-oxygen-cape-code.pdf.
\65\ Niklitschek and Secor (2009a, 2009b).
---------------------------------------------------------------------------
Criteria Expressed as Percent Oxygen Saturation
Finally, the EPA derived the proposed criteria in terms of percent
oxygen saturation, rather than in units of concentration (such as
milligrams per liter or mg/L) for two main reasons.\66\ First,
physiological effects of oxygen on aquatic organisms are directly
related to percent oxygen saturation and indirectly related to
dissolved oxygen concentration. As noted by Niklitschek and Secor
(2009a), percent oxygen saturation or partial pressure are the most
biologically relevant measures of oxygen because they determine the
maximum rate at which aquatic organisms may obtain oxygen from the
water. Second, percent oxygen saturation varies with water temperature
less than dissolved oxygen concentration. Because oxygen solubility is
higher in cold water than warm water, dissolved oxygen concentrations
are often much higher in cold water. The strong negative relationship
between dissolved oxygen concentration and temperature can complicate
the interpretation of seasonal dissolved oxygen patterns. For example,
in the Delaware River, dissolved oxygen concentrations increase quickly
during fall as temperatures decrease, even though percent saturation
increases more slowly. In this example, the increasing oxygen
concentration gives the appearance that oxygen availability to aquatic
organisms is increasing more rapidly than it is actually increasing.
For Atlantic Sturgeon, this means that low levels of percent oxygen
saturation may continue to impact growth and survival even though
dissolved oxygen concentrations increase. Given this relationship
between temperature and dissolved oxygen concentration, criteria
expressed as concentration will be above or below the protective
threshold at various times of the year as
[[Page 88325]]
temperature changes, whereas criteria expressed as percent oxygen
saturation can be protective throughout the year.
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\66\ Percent oxygen saturation and dissolved oxygen
concentration are two different ways to measure oxygen levels in
water. Dissolved oxygen concentration is the amount of oxygen
dissolved in the water, typically represented as milligrams of
oxygen per liter of water. Percent oxygen saturation is the ratio,
expressed as a percentage, of the dissolved oxygen concentration in
the water to the dissolved oxygen concentration when at equilibrium
with the atmosphere.
---------------------------------------------------------------------------
2. Proposed Dissolved Oxygen Criteria
The EPA's proposed dissolved oxygen criteria cover three distinct
seasons based largely on Atlantic Sturgeon early life stages and are
intended to protect all oxygen-sensitive species in the Delaware River,
as explained above. The Spawning and Larval Development season occurs
between March 1st and June 30th and captures a comprehensive range of
resident aquatic species' spawning periods.\67\ The Juvenile
Development season occurs between July 1st and October 31st and
captures critical early life stage growth and development for young-of-
the-year Atlantic Sturgeon. The Overwintering season occurs between
November 1st and February 28th (or 29th, in a leap year), when juvenile
Atlantic Sturgeon growth is limited by low water temperatures.
---------------------------------------------------------------------------
\67\ Stoklosa et al. (2018); Delaware River Basin Commission
(2015).
---------------------------------------------------------------------------
Each season has water quality criteria that each consist of three
components: magnitude, duration, and exceedance frequency. The
magnitude component indicates the required level of dissolved oxygen in
the water, which in this proposal is presented in units of percent
oxygen saturation. The duration component specifies the time period
over which water quality is averaged before comparison with the
criteria magnitude; in this proposal, the duration is a daily
average.\68\ The exceedance frequency component specifies how often
(e.g., percentage of the time) each criterion can be exceeded in each
season while still ensuring that the use is protected. For this
proposed rulemaking, the exceedance frequency is determined based on
the dissolved oxygen percentile from which the magnitude is derived
(i.e., the 10th percentile can be exceeded 10% of the time, which for a
season consisting of 123 days is 12 cumulative days of exceedance). For
dissolved oxygen, an exceedance occurs when the oxygen level in the
water is below the criterion value.
---------------------------------------------------------------------------
\68\ The EPA selected a daily average duration because it is a
readily measurable indicator of the oxygen levels at a daily
timescale. The daily average is protective because variability of
dissolved oxygen levels on a single day is small in the Delaware
River.
---------------------------------------------------------------------------
In this proposed rulemaking, the Spawning and Larval Development
and Overwintering seasons each have a single, identical dissolved
oxygen criterion with a magnitude of 66% oxygen saturation, a daily
average duration, and a 10% exceedance frequency (which allows for up
to 12 days of cumulative exceedance during each of these two seasons)
(Table 6 of this preamble). The Juvenile Development season has two
individually applicable dissolved oxygen criteria that together define
a protective seasonal distribution of percent oxygen saturation. The
criteria differ in both magnitude and exceedance frequency and both
levels must be attained. The first Juvenile Development criterion
defines the lower end of the distribution of oxygen levels and consists
of a magnitude of 66% oxygen saturation, a daily average duration, and
a 10% exceedance frequency (which allows for up to 12 days cumulative
exceedance during the season). The second Juvenile Development
criterion defines the center of the distribution and consists of a
magnitude of 74% oxygen saturation, a daily average duration, and a 50%
exceedance frequency (which allows for up to 61 days cumulative
exceedance during the season) (Table 6 of this preamble).
Table 6--The EPA's Proposed Dissolved Oxygen Criteria
----------------------------------------------------------------------------------------------------------------
Magnitude
(percent
Season oxygen Duration Exceedance frequency
saturation)
----------------------------------------------------------------------------------------------------------------
Spawning and Larval Development (March 1- 66 Daily verage.............. 10% (12 Days Cumulative).
June 30).
Juvenile Development (July 1-October 31) 66 Daily Average............. 10% (12 Days Cumulative).
74 Daily Average............. 50% (61 Days Cumulative).
Overwintering (November 1-February 28/ 66 Daily Average............. 10% (12 Days Cumulative).
29).
----------------------------------------------------------------------------------------------------------------
3. Alternative Options Considered
During the criteria derivation process, the EPA made several
decisions based on the best available sound scientific information to
ensure the dissolved oxygen criteria would be protective of the
applicable and proposed aquatic life designated uses. In this section,
the EPA presents three alternative options the Agency considered. For
each alternative, the EPA examined information currently available at
the time of this proposal. The EPA has concerns about whether each
alternative would be protective of the aquatic life designated uses
that include propagation; therefore, the EPA did not include any of
these alternatives as part of its lead proposed criteria. However, the
EPA requests comment and additional information on whether and how one
or more of these alternatives could protect the applicable and proposed
aquatic life designated uses in the specified zones of the Delaware
River and if so, what anticipated benefits would be associated with the
alternative compared to the EPA's proposed criteria.\69\
---------------------------------------------------------------------------
\69\ More information is available in the associated document,
Technical Support Document for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware River.
---------------------------------------------------------------------------
Alternative 1: Dissolved Oxygen Criteria Expressed as Concentration
(mg/L).
The EPA's proposed dissolved oxygen criteria are expressed as
percent oxygen saturation, as described in section IV.C.1 of this
preamble. However, the EPA recognizes that some stakeholders might be
more familiar with dissolved oxygen criteria expressed as concentration
or might have other reasons for preferring criteria expressed as
concentration. The EPA is seeking comment on whether dissolved oxygen
criteria expressed as concentration (mg/L) would be protective of
oxygen-sensitive species during each season.
To calculate Juvenile Development season criteria expressed as
concentration (mg/L), the EPA followed an analogous approach to the
method used for determining criteria as percent oxygen saturation, as
explained in section IV.C.1 of this preamble. The EPA used quantile
generalized additive models relating seasonal percentiles of dissolved
oxygen concentration to the expected median habitat suitability index
(HSI). The EPA selected as the alternative criteria values the
dissolved
[[Page 88326]]
oxygen concentration for which the expected median HSI is zero (Table 7
of this preamble).
To calculate dissolved oxygen criteria expressed as concentration
for the Spawning and Larval Development and Overwintering seasons, the
EPA started with the criteria computed as percent oxygen saturation
(Table 6 of this preamble) and converted each of these to a
concentration using each of the following two approaches, which
differed based on water temperature assumptions.\70\ The EPA's first
approach uses the 90th percentile of water temperatures in each season,
whereas the second approach uses the average water temperature in each
season.\71\ The 90th percentile approximates the highest water
temperature in each season, which corresponds to when dissolved oxygen
levels are generally at their lowest and therefore impacts to aquatic
life are most likely to occur. In the Delaware River, the highest
temperatures in the Spawning and Larval Development season occur in
late June and the highest temperatures in the Overwintering season
occur in early November. On the other hand, the EPA's second approach
using an average water temperature results in the concentration that
minimizes the magnitude of deviations in either direction from the
protective level across the season. Because the average water
temperature is lower than the 90th percentile water temperature, the
EPA's second approach resulted in higher dissolved oxygen
concentrations than the first approach (Table 7 of this preamble).
---------------------------------------------------------------------------
\70\ The EPA assumed salinity = 0 for each conversion from
percent oxygen saturation to concentration in the Spawning and
Larval Development and Overwintering seasons.
\71\ Seasonal 90th percentile and mean water temperature were
calculated using the daily climatology computed for Chester for
March 1, 2012-June 30th, 2022, for the Spawning and Larval
Development season and November 1, 2011-February 28, 2022, for the
Overwintering season.
---------------------------------------------------------------------------
In table 7 below, the EPA leads with alternative criteria based on
the 90th percentile water temperatures because existing dissolved
oxygen criteria guidance and criteria derivation efforts in other
states have commonly focused on the warmest conditions that occur,
which are the most critical for mitigating impacts to aquatic life due
to low oxygen.\72\ For consideration, the EPA presents alternative
criteria based on average water temperatures in parentheses.
---------------------------------------------------------------------------
\72\ United States Environmental Protection Agency. (2000).
Ambient Aquatic Life Water Quality Criteria for Dissolved Oxygen
(Saltwater): Cape Cod to Cape Hatteras. Document ID: EPA-822-R-00-
012. November 2000. https://www.epa.gov/sites/default/files/2018-10/documents/ambient-al-wqc-dissolved-oxygen-cape-code.pdf; Batiuk,
R.A., Breitburg, D.L., Diaz, R.J., Cronin, T.M., Secor, D.H., and
Thursby, G. (2009). Derivation of habitat-specific dissolved oxygen
criteria for Chesapeake Bay and its tidal tributaries. Journal of
Experimental Marine Biology and Ecology 381: S204-S215. https://doi.org/10.1016/j.jembe.2009.07.023.
Table 7--Alternative 1: Dissolved Oxygen Criteria Expressed as Concentration
[mg/L]
----------------------------------------------------------------------------------------------------------------
Water
Season temperature Magnitude (mg/ Duration Exceedance frequency
([deg]C) L)
----------------------------------------------------------------------------------------------------------------
Spawning and Larval Development * 23.3 (14.7) * 5.6 (6.7) Daily Average........ 10% (12 Days
(March 1-June 30). Cumulative).
Juvenile Development (July 1- \+\ N/A 5.4 Daily Average........ 10% (12 Days
October 31). Cumulative).
N/A \+\........................... 6.1 Daily Average 50% (61 Days
Cumulative).
Overwintering (November 1-February * 12.4 (5.6) * 7.0 (8.3) Daily Average........ 10% (12 Days
28/29). Cumulative).
----------------------------------------------------------------------------------------------------------------
* The 90th percentile of seasonal water temperature and corresponding criterion is used for the main estimate,
while the average water temperature and corresponding criterion is shown in parentheses.
\+\ Water temperature is not applicable during the Juvenile Development season because the criteria magnitudes
are derived from the EPA's Atlantic Sturgeon cohort model, described in section IV.C.1 of this preamble.
Concentration-based criteria derived using the EPA's first approach
(based on the 90th percentile water temperatures) would be equivalent
to the EPA's proposed 66% oxygen saturation when water temperature is
near the 90th percentile temperature and oxygen is near the lowest
point in each season. However, during periods in each season when water
temperature is lower than the 90th percentile temperature, the
concentration-based criteria would be below the level that is
equivalent to the EPA's proposed 66% oxygen saturation level. For
example, when water temperature is 2 [deg]C in mid-winter, oxygen
saturation is 66% when the dissolved oxygen concentration is 9.1 mg/L.
The EPA therefore has concerns about whether dissolved oxygen criteria
expressed as concentration for this alternative would be protective for
the Spawning and Larval Development and Overwintering seasons. Similar
to the first approach, the concentration derived using the EPA's second
approach (average water temperature) is also below the level that is
equivalent to 66% oxygen saturation when water temperature is below the
seasonal average. During periods in each season when the water
temperature is warmer than the average, concentrations calculated using
the EPA's second approach would result in an oxygen saturation higher
than 66%.\73\
---------------------------------------------------------------------------
\73\ More information on dissolved oxygen trends in the
specified zones of the Delaware River is available in the associated
rule documents, Technical Support Document for the Proposed Rule:
Water Quality Standards to Protect Aquatic Life in the Delaware
River and Economic Analysis for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware River.
---------------------------------------------------------------------------
The EPA provided the concentrations in table 7 of this preamble
that result from the methods described above to help facilitate public
comment. The EPA also requests public input and supporting information
about other ways the Agency could develop dissolved oxygen criteria
expressed as concentration--particularly for the Spawning and Larval
Development and Overwintering seasons--to protect the relevant aquatic
life uses in accordance with the CWA.
Alternative 2: Single Dissolved Oxygen Criterion During the
Juvenile Development Season with a 10% Exceedance Frequency.
The EPA's proposed dissolved oxygen criteria for the critical
Juvenile Development season consist of two values--one that may be
exceeded 10% of the time and one that may be exceeded 50% of the time--
that must both be met during the season, as explained in section IV.C.1
of this preamble. However, the EPA recognizes that some stakeholders
might prefer the simpler criteria framework a single criterion would
afford or may have other reasons for preferring a single value.
[[Page 88327]]
The EPA is seeking comment and supporting information on applying a
single dissolved oxygen criterion with a 10% exceedance frequency
during the Juvenile Development season, including whether criteria
expressed with a single criterion would protect the applicable and
proposed aquatic life designated uses. This could mean applying a
single criterion of 66% oxygen saturation (or 5.4 mg/L, if expressed as
concentration) with a 10% exceedance frequency for the Juvenile
Development season. The Overwintering and Spawning and Larval
Development seasons are unaffected by this alternative.
The EPA also requests public input and supporting information about
other potential options the Agency could consider for dissolved oxygen
criteria in the form of a single criterion to protect the aquatic life
uses in accordance with the CWA.
Alternative 3: Inclusion of a 1-in-3-Year Interannual Exceedance
Frequency.
The EPA's proposed criteria do not include an interannual
exceedance frequency and therefore would need to be met every year.
However, the EPA recognizes that some stakeholders might prefer
criteria with an interannual exceedance frequency to help accommodate
the impact of environmental variability on dissolved oxygen conditions
in the specified zones of the Delaware River. The EPA is seeking
comment and supporting information on the addition of a 1-in-3-year
interannual exceedance frequency as part of the dissolved oxygen
criteria. The EPA is particularly interested in how and why this
approach would protect the applicable and current aquatic life uses.
If a 1-in-3-year interannual exceedance frequency were included as
part of the dissolved oxygen criteria, it would mean that in any three-
year period, all criteria would need to be attained in at least two
years. An exceedance would occur in any year where one or more of the
criteria were not attained. The following two examples describe how a
1-in-3-year interannual exceedance frequency could function.
Example 1: If, in a given year, the dissolved oxygen during the
Juvenile Development season fell below 66% saturation more than 10% of
the time, then that year would not meet the Juvenile Development 10th
percentile criterion. Therefore, that year would count as one year of
exceedance towards the 1-in-3-year interannual exceedance frequency. If
another criterion, for example the Spawning and Larval Development
criterion, was not met in that same year, then it would still only
count as one year of exceedance despite the fact that two criteria were
not met that year (Table 8 of this preamble).
Table 8--Example 1 Scenario Where Dissolved Oxygen Criteria With the 1-in-3-Year Interannual Exceedance
Frequency Are Met
----------------------------------------------------------------------------------------------------------------
Was the seasonal criterion met?
Season --------------------------------------------------------------------------
Year 1 Year 2 Year 3
----------------------------------------------------------------------------------------------------------------
Spawning and Larval Development...... No..................... Yes.................... Yes.
Juvenile Development--10th Percentile No..................... Yes.................... Yes.
Juvenile Development--50th Percentile Yes.................... Yes.................... Yes.
Overwintering........................ Yes.................... Yes.................... Yes.
Does the Full Year Meet Criteria?.... No..................... Yes.................... Yes.
----------------------------------------------------------------------------------------------------------------
Example 2: If, in a given year, the dissolved oxygen during the
Juvenile Development season fell below 66% saturation more than 10% of
the time, then that year would not meet the Juvenile Development 10th
percentile criterion. If the following year, the Juvenile Development
season fell below 74% saturation more than 50% of the time, then that
year would not meet the Juvenile Development 50th percentile criterion
(Table 9 of this preamble). In this scenario, the first and second year
in the three-year period both did not meet the criteria; therefore, the
interannual exceedance frequency was not met.
Table 9--Example 2 Scenario Where Dissolved Oxygen Criteria With the 1-in-3-Year Interannual Exceedance
Frequency Are Not Met
----------------------------------------------------------------------------------------------------------------
Was the seasonal criterion met?
Season --------------------------------------------------------------------------
Year 1 Year 2 Year 3
----------------------------------------------------------------------------------------------------------------
Spawning and Larval Development...... Yes.................... Yes.................... Yes.
Juvenile Development--10th Percentile No..................... Yes.................... Yes.
Juvenile Development--50th Percentile Yes.................... No..................... Yes.
Overwintering........................ Yes.................... Yes.................... Yes.
Does the Full Year Meet Criteria?.... No..................... No..................... Yes.
----------------------------------------------------------------------------------------------------------------
The EPA has historically considered it appropriate to apply a 1-in-
3-year exceedance frequency in the context of aquatic life criteria for
toxic pollutants, based on the ability of aquatic ecosystems to recover
from criteria exceedances and natural variations in flow and the
concentrations of the pollutant in a waterbody.\74\ However, the EPA
does not typically apply this construct to criteria for conventional
water quality parameters like dissolved
[[Page 88328]]
oxygen due to inherent differences between these parameters and toxic
pollutants. For example, dissolved oxygen is typically not directly
regulated in the same manner as toxic pollutants because low dissolved
oxygen conditions (such as hypoxia) are a symptom of a related issue,
such as nutrient or ammonia pollution.\75\ The EPA also requests public
input and supporting information regarding any scientific approaches
that can be used to predict the impact of periodic low oxygen levels on
populations of aquatic organisms.
---------------------------------------------------------------------------
\74\ Stephen, C.E., Mount, D.I., Hansen, D.J., Gentile, J.R.,
Chapman, G.A., and Brungs, W.A. (1985). Guidelines for Deriving
Numerical National Water Quality Criteria for the Protection of
Aquatic Organisms and Their Uses. United States Environmental
Protection Agency. Document ID: PB85-227049. https://www.epa.gov/sites/default/files/2016-02/documents/guidelines-water-quality-criteria.pdf; United States Environmental Protection Agency. (2023).
Proceedings from the EPA Frequency and Duration Experts Workshop:
September 11-12, 2019. Document ID: EPA-820-R-23-002. February 2023.
https://www.epa.gov/system/files/documents/2023-02/proceedings-frequency-duration-workshop.pdf.
\75\ United States Environmental Protection Agency. (2000).
Ambient Aquatic Life Water Quality Criteria for Dissolved Oxygen
(Saltwater): Cape Cod to Cape Hatteras. Document ID: EPA-822-R-00-
012. November 2000. https://www.epa.gov/sites/default/files/2018-10/documents/ambient-al-wqc-dissolved-oxygen-cape-code.pdf.
---------------------------------------------------------------------------
V. Endangered Species Act Consultation
Section 7(a)(2) of the Endangered Species Act (ESA) requires that
each Federal Agency ensure that any action authorized, funded, or
carried out by such Agency is not likely to jeopardize the continued
existence of any endangered or threatened species or result in the
destruction or adverse modification of critical habitat. Pursuant to
section 7(a)(2) of the ESA, the EPA will consult with NOAA Fisheries
concerning this rulemaking action proposing a designated aquatic life
use including propagation and associated dissolved oxygen criteria in
the specified zones of the Delaware River. The EPA will work closely
with NOAA Fisheries to ensure that any WQS the Agency finalizes are not
likely to jeopardize the continued existence of any endangered or
threatened species or result in the destruction or adverse modification
of designated critical habitat in the specified zones of the Delaware
River. As a result of this consultation, the EPA may modify some
provisions of this proposed rule.
VI. Applicability
The EPA is proposing a Federal designated use that would apply in
New Jersey and Pennsylvania, in addition to those states' designated
uses that are already applicable. This means that for the specified
zones of the Delaware River, the EPA is proposing to supplement, rather
than replace, New Jersey's and Pennsylvania's currently applicable
aquatic life designated uses. Therefore, New Jersey's and
Pennsylvania's currently applicable aquatic life designated uses would
remain applicable for CWA purposes. Those states' current water quality
criteria associated with those uses would also remain applicable for
CWA purposes, with the exception of any aquatic life criteria for
dissolved oxygen, which would be replaced by the criteria that the EPA
promulgates through this rulemaking, if finalized.\76\ The EPA
concluded that this approach was the best way to make clear which of
the states' WQS would and would not be revised by this rulemaking, if
finalized. The EPA requests comment on this approach.
---------------------------------------------------------------------------
\76\ In the December 1, 2022, Administrator's Determination, the
EPA determined that revised dissolved oxygen criteria are necessary
to protect a propagation designated use. This proposed rulemaking
includes dissolved oxygen criteria that are protective of all life
stages of resident and migratory aquatic life species in the
Delaware River (section IV.C. of this preamble).
---------------------------------------------------------------------------
In addition, the EPA is proposing dissolved oxygen criteria that
would replace Delaware's, New Jersey's, and Pennsylvania's existing
dissolved oxygen criteria for the specified zones of the Delaware
River. The EPA notes that there are aquatic life criteria for
pollutants and parameters other than dissolved oxygen that are in
effect for CWA purposes--not only in the zones covered by this proposed
rulemaking, but also for other zones of the Delaware River that already
include aquatic life propagation as a designated use; those criteria
are not impacted by this rulemaking.
Since the EPA is only proposing to promulgate revised dissolved
oxygen criteria for the specified zones of the Delaware River,
Delaware, New Jersey, and Pennsylvania should evaluate whether other
aquatic life criteria should similarly be added or revised for the
specified zones or other zones of the Delaware River. One way these
states can review their WQS is through the triennial review process. As
explained in section III of this preamble, states must review their WQS
at least once every three years and, if appropriate, revise standards
or adopt new standards (40 CFR 131.20(a)). The EPA recommends that
Delaware, New Jersey, and Pennsylvania review their existing aquatic
life criteria during their next triennial review to determine if new or
revised aquatic life criteria would be appropriate to protect all
applicable aquatic life designated uses, including any Federal
designated use that the EPA may promulgate as part of a final rule.
VII. Conditions Where Federal Water Quality Standards Would Not Be
Promulgated or Would Be Withdrawn
As noted, under the CWA, states and authorized tribes have the
primary responsibility for developing and adopting WQS for their
navigable waters (CWA section 303(a) through (c)). Although the EPA is
proposing a revised aquatic life designated use and protective
dissolved oxygen criteria for the specified zones of the Delaware
River, each state retains the option to adopt and submit to the EPA for
review its own revised designated use and dissolved oxygen criteria
that are consistent with CWA section 303(c) and the EPA's implementing
regulation to address the EPA's Administrator's Determination.
A. Conditions Where Federal Standards Would Not Be Promulgated
If Delaware, New Jersey, and Pennsylvania adopt and submit revised
WQS that addresses the EPA's December 1, 2022, Administrator's
Determination, and the EPA approves those WQS before finalizing this
proposed rulemaking, then a Federal promulgation would no longer be
required under the CWA. Similarly, if one state adopts and submits WQS
consistent with this proposed rulemaking, and the EPA approves those
WQS before finalizing this proposed rulemaking, then a Federal
promulgation would no longer be required under the CWA for that state.
B. Conditions Where Federal Standards Would Be Withdrawn
If the EPA finalizes this proposed rulemaking and Delaware, New
Jersey, and Pennsylvania subsequently adopt and submit revised WQS to
the EPA, and the EPA approves those WQS, then the EPA would undertake a
rulemaking to withdraw the federally promulgated use and/or dissolved
oxygen criteria (40 CFR 131.21(c)). Similarly, if one state adopts and
submits revised WQS to the EPA, and the EPA approves those WQS, then
the EPA would undertake a rulemaking to withdraw the federally
promulgated WQS for that state.
If Delaware's, New Jersey's, and/or Pennsylvania's adopted
dissolved oxygen criteria are as stringent or more stringent than the
federally promulgated criteria, then that state's criteria would
immediately become the CWA-applicable criteria upon the EPA's approval.
If Delaware's, New Jersey's, and/or Pennsylvania's adopted dissolved
oxygen criteria are less stringent than the federally promulgated
criteria, and the EPA approves those less stringent criteria, then
those EPA-approved criteria would become the applicable criteria for
CWA purposes only after the EPA withdraws its federally promulgated
criteria for the relevant state(s).
[[Page 88329]]
VIII. Alternative Regulatory Approaches and Implementation Mechanisms
The Federal WQS regulations at 40 CFR part 131 provide several
approaches that Delaware, New Jersey, and Pennsylvania could use at
each state's discretion when implementing or deciding how to implement
the federally promulgated dissolved oxygen criteria, if finalized. The
EPA has identified two approaches--WQS Variances and NPDES Permit
Compliance Schedules--that might be of particular interest for the
states covered by this proposed rulemaking. Additionally, the EPA
included a discussion about CWA section 303(d)/305(b) water quality
assessments to clarify potential options that may be available to
states in the specific circumstances relevant to this rulemaking.
A. Water Quality Standards Variances
A WQS variance is a time-limited designated use and criterion, for
a specific pollutant or water quality parameter, that reflects the
highest attainable condition (HAC) during the term of the WQS variance
(40 CFR 131.3(o)). WQS variances can be used to incrementally improve
water quality where the designated use and criterion are unattainable
for a period of time. The state would need to demonstrate that
attaining the applicable designated use and dissolved oxygen criterion
would not be feasible for a period of time (i.e., during the term of
the WQS variance) because of one of the factors specified in 40 CFR
131.14(b)(2)(i)(A) and specify the actions that will be taken to make
incremental water quality improvements during the term of the WQS
variance.
If Delaware, New Jersey, and/or Pennsylvania choose/s to adopt a
WQS variance, the state/s must specify in the WQS variance the term and
the interim requirements of the WQS variance. The term must be
justified by describing the pollutant control activities expected to
occur over that term to achieve the HAC. The interim requirements must
be a quantitative expression that reflects the HAC using one of the
options provided at 40 CFR 131.14(b)(1)(ii).
WQS variances adopted in accordance with 40 CFR 131.14 and approved
by the EPA for CWA purposes provide a legal avenue for states to write
NPDES permit limits that are based on the HAC during the term of the
WQS variance, while simultaneously implementing controls to make
incremental water quality improvements toward ultimately attaining the
applicable designated use and dissolved oxygen criterion.
B. NPDES Permit Compliance Schedules
The EPA's regulations at 40 CFR 122.47 and 131.15 address how
permitting authorities can use schedules for compliance with a water-
quality-based effluent limitation (WQBEL) in an NPDES permit, if the
discharger needs time to undertake an enforceable sequence of actions--
such as facility upgrades or operation changes--leading to compliance
with the WQBEL. The EPA's regulation at 40 CFR 122.47 allows states
authorized to administer the NPDES program to include compliance
schedules in NPDES permits, when appropriate and where authorized by
the state's WQS, provided the compliance schedule authorizing provision
was approved by the EPA. Such compliance schedules may be used to
implement any CWA-effective WQS, including any WQS that the EPA
promulgates as part of a final rule.
C. Clean Water Act Section 303(d)/305(b) Water Quality Assessments
If the EPA promulgates revised aquatic life WQS for the specified
zones of the Delaware River and they become effective for CWA purposes,
Delaware, New Jersey, and Pennsylvania will have an obligation under
CWA sections 303(d) and 305(b) to assess whether the WQS are being
attained. The EPA anticipates there may be a period of time immediately
after promulgation of the revised WQS when the WQS will not be attained
because the actions and procedures required to achieve compliance will
take time to implement. In this scenario, any of the relevant zones not
attaining the WQS should be classified as impaired on the relevant
303(d)/305(b) Integrated Report(s) (IR) that is submitted to the EPA
for review.
Per the CWA and the EPA's implementing regulations, waters that are
assessed as impaired by a pollutant typically require the development
of a Total Maximum Daily Load (TMDL), which is a regulatory planning
tool designed to restore water quality via allocations of pollutant
reductions to relevant point and non-point sources. The EPA regulations
also recognize that other pollution control requirements may obviate
the need for a TMDL. Specifically, impaired waters do not require a
TMDL if: (1) technology-based effluent limitations required by the CWA;
(2) more stringent effluent limitations required by a state, local, or
Federal authority; or (3) other pollution control requirements (e.g.,
best management practices) required by a state, local, or Federal
authority are stringent enough to implement applicable WQS (40 CFR
130.7(b)(1)). Impaired waters that do not require a TMDL because they
satisfy one of these alternatives are commonly referred to as Category
4b waters, as described in the EPA's Integrated Reporting Guidance for
CWA sections 303(d), 305(b), and 314.\77\
---------------------------------------------------------------------------
\77\ The EPA's Integrated Reporting Guidance is available at:
https://www.epa.gov/tmdl/integrated-reporting-guidance-under-cwa-sections-303d-305b-and-314.
---------------------------------------------------------------------------
DRBC developed a model to evaluate sources of pollution that affect
dissolved oxygen levels in the specified zones of the Delaware River
and concluded that point sources are the primary contributor to oxygen
depletion within those zones.\78\ DRBC therefore concluded that further
controls on point sources are needed to achieve dissolved oxygen water
quality conditions that support aquatic life designated uses that
include propagation in the specified zones. The EPA's economic analysis
evaluates point source controls that are expected to result in
dissolved oxygen levels that meet EPA's proposed criteria.\79\ If,
after finalization of this rulemaking, DRBC, Delaware, New Jersey, or
Pennsylvania require effluent limitations and/or other pollution
control requirements that the EPA agrees are stringent enough to
implement the final dissolved oxygen criteria, the specified zones may
be a candidate for Category 4b in future IRs. The EPA will work with
Delaware, New Jersey, and Pennsylvania, in consultation with DRBC, on
future IRs to determine the appropriate assessment status for the
waters that are subject to this rulemaking.
---------------------------------------------------------------------------
\78\ Delaware River Basin Commission (2022a, 2022b).
\79\ More details are available in the document, Economic
Analysis for the Proposed Rule: Water Quality Standards to Protect
Aquatic Life in the Delaware River.
---------------------------------------------------------------------------
IX. Economic Analysis
The EPA conducted an economic analysis to evaluate the potential
costs and benefits associated with this proposed rulemaking. In the
high-level summary of the EPA's economic analysis below, the EPA first
describes a baseline scenario that is intended to characterize the
world in the absence of the EPA's proposed rule. Next, the EPA
describes development of a policy scenario based on potential pollution
control actions that, if implemented, can be expected to meet the EPA's
proposed dissolved oxygen criteria. Finally, the EPA evaluates the
anticipated costs and benefits associated with the policy scenario and
the EPA's proposed criteria. More details and information
[[Page 88330]]
are available in the associated document, Economic Analysis for the
Proposed Rule: Water Quality Standards to Protect Aquatic Life in the
Delaware River.
A. Baseline for the Analysis
The baseline is intended to characterize the world in the absence
of the EPA's proposed rule. The EPA typically assumes full compliance
with existing regulations and requirements--including CSO long-term
control plans (LTCPs)--even if they are not yet fully implemented, as a
basis for estimating the cost and benefits of proposed regulations.
This baseline approach ensures that the cost and benefits of the
existing regulations and requirements are not double counted.
In this economic analysis, the EPA assumes that without the
proposed rule, the less stringent WQS (that do not support aquatic life
propagation) currently in effect for CWA purposes would remain in
effect (section III.D. of this preamble). Accordingly, the EPA assumes
that water quality conditions in the specified zones of the Delaware
River, particularly during the Juvenile Development season (July 1-
October 31), would continue to experience low oxygen levels that do not
support aquatic life propagation, even with implementation of existing
and planned CSO LTCPs.\80\ Along the specified zones of the Delaware
River, there are three combined sewer systems with CSO LTCPs that are
relevant for consideration by the EPA as part of the baseline. The
Philadelphia Water Department, Camden County Municipal Utilities
Authority, and Delaware County Regional Water Quality Control Authority
all have LTCPs that are either approved or in progress.\81\ The EPA
expects implementation of these LTCPs, when finalized, to occur
regardless of the EPA's proposed rule. Therefore, the EPA included
estimated CSO volume reductions for these three dischargers as part of
the baseline for this economic analysis.
---------------------------------------------------------------------------
\80\ While the EPA normally assumes full compliance with
existing LTCPs, for this proposed rulemaking, the EPA is also
assuming full compliance with planned LTCPs. Because planned LTCPs
are not final and therefore are subject to change, this adds
uncertainty to the baseline conditions.
\81\ Delaware River Basin Commission (2022a); DELCORA. (2023).
Combined Sewer System: DELCORA CSO LTCP. https://www.delcora.org/combined-sewer-systems/delcora-cso-ltcp/; Philadelphia Water
Department. (2023). CSO Long Term Control Plan. https://water.phila.gov/reporting/ltcp/; State of New Jersey Division of
Water Quality. (2023). Long Term Control Plan Submittals. https://www.nj.gov/dep/dwq/cso-ltcpsubmittals.htm.
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DRBC modeled the effect of pollution reduction on dissolved oxygen
levels in the Delaware River and provided the EPA with water quality
simulation results under both baseline and ``restored'' conditions for
the years 2012, 2018, and 2019.\82\ Baseline simulations predict water
quality conditions associated with the discharge of actual wastewater
treatment plant (WWTP) flows at existing levels of treatment and after
full implementation of LTCPs. The restored simulations predict water
quality conditions associated with the discharge of actual WWTP flows
at treatment levels that include additional effluent treatment and
after full implementation of LTCPs.
---------------------------------------------------------------------------
\82\ The EPA determined that the model runs from DRBC were
sufficient for use in this economic analysis.
---------------------------------------------------------------------------
Of the three available years (2012, 2018, and 2019), the EPA
selected the 2019 year as representative of the most typical conditions
in the relevant zones of the Delaware River. In comparison, 2012 had
atypically poor conditions (low percent oxygen saturation, high water
temperature), while 2018 had atypically good conditions (high percent
oxygen saturation, low water temperature). Therefore, model runs used
in this economic analysis are based on 2019 conditions.
B. Development of the Policy Scenario
There is a wide range of potential paths that Delaware, New Jersey,
and Pennsylvania may choose to take when implementing the EPA's
proposed WQS. For this economic analysis, the EPA relied on available
data to develop a policy scenario based on modeled pollution controls
developed by DRBC that the EPA expects would meet the Agency's proposed
dissolved oxygen criteria. Actual benefits, costs, and impacts will
depend on the choices that states would make in implementing the
proposed WQS, which may differ from the policy scenario in this
economic analysis.
The EPA's proposed dissolved oxygen criteria apply to three seasons
(section IV.C. of this preamble). Therefore, when developing a policy
scenario for this proposed rulemaking, the EPA evaluated potential
pollution control actions that would be expected to meet the EPA's
criteria in each of the three seasons. The EPA began by evaluating
water quality monitoring data for the past decade from two continuous
monitoring stations in the relevant zones of the Delaware River--Penn's
Landing in Zone 3 and Chester in Zone 4. Based on the monitoring data,
the EPA expects that the Agency's proposed dissolved oxygen criteria
for the Spawning and Larval Development and Overwintering seasons will
likely be met without the need for additional WWTP upgrades or other
controls beyond the baseline conditions (i.e., the LTCPs). Monitoring
data for the Juvenile Development season indicated that additional
pollution control actions are likely necessary to meet the EPA's
proposed criteria in that season. To develop a policy scenario for the
Juvenile Development season, the EPA relied on modeled data from DRBC
predicting oxygen levels in 2019 in the specified zones of the Delaware
River following a set of WWTP pollution control actions for certain
dischargers. Modeled data for restored conditions are described in the
baseline section above, while WWTP controls are described in the cost
section below. The EPA expects that this policy scenario (hereafter,
the ``2019 restored scenario'') will meet the proposed criteria during
the Juvenile Development season.
C. Potential Costs
The EPA estimated compliance costs for the proposed WQS based on
estimates for WWTPs to reduce effluent ammonia nitrogen concentrations
and raise effluent dissolved oxygen concentrations. Although there are
several causes that contribute to low dissolved oxygen conditions in
the specified zones of the Delaware River, DRBC identified ammonia
nitrogen loadings from WWTPs as the leading cause of oxygen-depletion
in the river.\83\ As a result, for the purpose of this economic
analysis, the EPA assumed that additional pollution control
technologies implemented at WWTPs is the most likely way that Delaware,
New Jersey, and Pennsylvania will implement the proposed WQS.
Therefore, the EPA evaluated WWTP controls rather than other non-point
source controls for this cost analysis.
---------------------------------------------------------------------------
\83\ Delaware River Basin Commission (2022a).
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The EPA relied on cost information from several DRBC studies to
estimate the costs of achieving the proposed WQS.\84\ DRBC's 2022
Analysis of Attainability report categorized WWTPs as either class A',
A, or B facilities. DRBC determined that discharges from Class A', A,
and B facilities have a major
[[Page 88331]]
impact, a marginal impact, or no measurable impact on oxygen levels in
the specified zones, respectively. The EPA's 2019 restored scenario
follows DRBC's approach by including the seven Class A' and two Class A
facilities and excluded the three Class B facilities.\85\
---------------------------------------------------------------------------
\84\ Id.; Kleinfelder Inc. (2021). Nitrogen Reduction Cost
Estimation Study Final Summary Report. https://www.nj.gov/drbc/library/documents/NitrogenReductionCostEstimates_KleinfelderJan2021.pdf; Kleinfelder
Inc. (2023). Delaware River Basin Commission Nitrogen Reduction Cost
Estimation Study--Supplemental Cost Addendum 2 Technical
Memorandum--Final. https://www.nj.gov/drbc/library/documents/NitrogenReductionCostEstimates_Kleinfelder_aug2023addendum.pdf.
\85\ Delaware River Basin Commission (2022a).
---------------------------------------------------------------------------
The EPA used WWTP-specific (capital, operations and maintenance
(O&M)) compliance costs from Kleinfelder Inc. (2021, 2023) to estimate
compliance costs, based on the discharger classification. Total
compliance costs include the costs associated with both of the
following:
1. Class A' Facilities: Costs associated with reductions in
effluent ammonia nitrogen concentrations to 1.5 mg/L from May 1 through
October 31 and increases in effluent oxygen concentrations to a monthly
average of 6 mg/L year-round for the seven WWTPs categorized as Class
A' facilities.
2. Class A Facilities: Costs associated with reductions in effluent
ammonia nitrogen concentrations to 5 mg/L from May 1 through October 31
for the two WWTPs categorized as Class A facilities.
To estimate annualized compliance costs, the EPA assumed capital
costs occur upfront in 2024 followed by a 5-year construction period.
Consistent with Kleinfelder Inc. (2021, 2023), the EPA assumed O&M
costs occur over a 25-year period from 2029 through 2053. The EPA thus
annualized costs over a 30-year analysis period between 2024 and 2053
and discounted all cost values to 2024, using a 3 percent discount
rate.
Table 10 of this preamble presents the annualized compliance costs
associated with achieving the EPA's proposed WQS, using a 3 percent
discount rate. The estimated total annualized compliance cost across
nine WWTPs is $137.1 million (2022$). These costs vary considerably
between the nine WWTPs, ranging from $1.9 million at the Lower Bucks
County Joint Municipal Authority WWTP to $37.6 million at the
Philadelphia Water Department (PWD) Southwest Water Pollution Control
Plant (2022$). Among the dischargers, PWD bears the highest proportion
of total costs, with its three facilities' combined costs accounting
for over 50 percent of total costs. Overall, 66 percent of the costs
are attributable to capital and 34 percent are attributable to O&M.
Table 10--Annualized Compliance Costs Using a 3 Percent Discount Rate
[Million 2022$]
----------------------------------------------------------------------------------------------------------------
Annualized costs
Plant State Class (millions 2022$)
----------------------------------------------------------------------------------------------------------------
Camden County Municipal Utilities NJ........................ A'........................ $16.2
Authority.
City of Wilmington................... DE........................ A'........................ 23.9
Delaware County Regional Water DE........................ A'........................ 9.1
Pollution Control Authority.
Gloucester County Utilities Authority NJ........................ A'........................ 4.9
PWD Northeast Water Pollution Control PA........................ A'........................ 26.2
Plant.
PWD Southeast Water Pollution Control PA........................ A'........................ 14.1
Plant.
PWD Southwest Water Pollution Control PA........................ A'........................ 37.6
Plant.
Hamilton Township.................... NJ........................ A......................... 3.3
Lower Bucks County Joint Municipal PA........................ A......................... 1.9
Authority.
------------------
Total............................ .......................... .......................... 137.1
----------------------------------------------------------------------------------------------------------------
D. Potential Benefits
Water quality improvements can have a wide range of effects on
water resources and the environmental goods and services that they
provide, including services valued by people (e.g., recreation,
commercial fishing, public and private property ownership, existence
services such as aquatic life, wildlife, and habitat designated uses).
Some environmental goods and services (e.g., commercially caught fish)
are traded in markets, and thus their value can be directly observed.
Other environmental goods and services (e.g., recreation and support of
aquatic life) cannot be bought or sold directly and thus do not have
observable market values. This second type of environmental goods and
services are classified as ``non-market.'' The estimated changes in the
non-market values of the water resources affected by the EPA's proposed
WQS (hereafter, ``non-market benefits'') are additive to market values
(e.g., avoided costs of producing various market goods and services).
To value non-market benefits, the EPA used a benefit transfer
approach based on a meta-analysis of surface water valuation studies to
evaluate the use and nonuse benefits of improved surface water quality
resulting from achievement of the EPA's proposed WQS in the 2019
restored scenario.\86\ The benefit transfer approach involves three
main steps:
---------------------------------------------------------------------------
\86\ The EPA has used this benefit transfer approach on numerous
occasions, most recently in the Benefit and Cost Analysis for
Proposed Revisions to the Effluent Limitations Guidelines and
Standards for the Steam Electric Power Generating Point Source
Category, which is available at https://www.epa.gov/system/files/documents/2023-03/steam-electric-benefit-cost-analysis_proposed_feb-2023.pdf.
---------------------------------------------------------------------------
1. Estimating water quality improvements associated with attainment
of the EPA's proposed WQS relative to the baseline;
2. Translating these improvements into a water quality index (WQI)
that can be linked to ecosystem services and uses that are valued by
society. The WQI used for this analysis includes six parameters:
dissolved oxygen, biological oxygen demand (BOD), fecal coliform (FC),
total nitrogen (TN), total phosphorus (TP), and total suspended solids
(TSS); and
3. Estimating the dollar value of the estimated water quality
improvements based on estimates of the public's willingness-to-pay
(WTP) derived from a meta-analysis of surface water valuation studies.
To estimate changes in ecosystem services provided in the specified
zones of the Delaware River following attainment of the proposed WQS,
the EPA obtained water quality modeling data from DRBC, including
dissolved oxygen, TN, and TP levels for various effluent treatment
scenarios. The EPA used DRBC's modeled output of dissolved oxygen
levels in the specified zones following implementation of effluent
controls (described in the cost section) and based on 2019 conditions
(as described in the policy scenario
[[Page 88332]]
section). The EPA used the 2019 restored scenario as the basis for
representing conditions following the implementation of the proposed
WQS, while making minor adjustments as needed \87\ to ensure that
predicted oxygen levels meet the EPA's proposed WQS. This analysis
provides insight into the water quality improvements and benefits that
are likely to result from implementation of the proposed WQS. For the
remaining parameters included in the WQI (i.e., BOD, FC, and TSS), the
EPA relied on measured data at various locations within the specified
zones.
---------------------------------------------------------------------------
\87\ Adjustments are detailed in section 4.2 of the associated
document, Economic Analysis for the Proposed Rule: Water Quality
Standards to Protect Aquatic Life in the Delaware River.
---------------------------------------------------------------------------
The effluent treatment measures implemented in response to the
proposed WQS would directly affect the amount of ammonia nitrogen
discharged to the specified zones of the Delaware River and therefore
also reduce BOD. However, DRBC's model does not account for the changes
in BOD. The EPA approximated BOD concentrations following effluent
treatment by assuming that baseline BOD concentrations are reduced by
the same percentage change that dissolved oxygen improves within each
zone (i.e., Zone 3, 4, and Upper 5) of the model. The EPA kept levels
for the remaining parameters (TN, TP, TSS, and FC) unchanged from
baseline conditions.
Table 11 of this preamble summarizes the percent change in
dissolved oxygen and BOD by zone between the baseline and the 2019
restored scenario.
Table 11--Dissolved Oxygen and Biological Oxygen Demand Changes Between
the Baseline and 2019 Restored Scenarios
------------------------------------------------------------------------
Percent change
Zone from baseline
\a\
------------------------------------------------------------------------
3....................................................... 10.8
4....................................................... 23.8
Upper-5................................................. 8.8
------------------------------------------------------------------------
\a\ The percent change for dissolved oxygen and biological oxygen demand
are the same, but in opposite directions, i.e., the percent decrease
in biological oxygen demand concentration is the same as the percent
increase in dissolved oxygen concentration.
To quantify benefits of water quality improvements, as is
consistent with past practice, the EPA analyzed the values held by
households residing within 100 miles of the specified zones of the
Delaware River for water quality improvements associated with the EPA's
proposed WQS.\88\ Households may consider waters unaffected by the
EPA's proposed WQS to be substitute waters for those affected, and this
can influence what households would be willing to pay for improvements
associated with the proposed WQS. The EPA deems waters unaffected by
the proposed WQS within the 100-mile buffer around each Census block
group as viable substitutes.
---------------------------------------------------------------------------
\88\ The EPA's 100-mile radius assumption follows Viscusi et al.
(2008), which states: `The survey defined relevant water quality as
residing in a region that is ``a 2-hour drive or so of your home, in
other words, within 100 miles.'' About 80% of all recreational uses
of bodies of water are within such a radius of users' homes. This
80% figure was based on data generated by EPA from the 1996 National
Survey on Recreation and the Environment. Data indicates that 77.9%
of boating visits, 78.1% of fishing visits, and 76.9% of swimming
recreational visits are within a 100-mile radius of a given
waterbody. (Citation: Viscusi, W. K., Huber, J., & Bell, J. (2008).
The economic value of water quality. Environmental and resource
economics, 41(2), 169-187.)
---------------------------------------------------------------------------
The EPA estimated the economic value of water quality changes using
results of a meta-analysis of 189 estimates of total WTP (including
both use and nonuse values) for water quality improvements, provided by
59 original studies conducted between 1981 and 2017. The estimated
econometric model allows calculation of total WTP for changes in a
variety of environmental services affected by water quality and valued
by people, including changes in recreational fishing opportunities,
other water-based recreation, and existence services such as aquatic
life, wildlife, and habitat designated uses. The model also allows the
EPA to adjust WTP values based on the core geospatial factors predicted
by theory to influence WTP, including: scale (the size of affected
resources or areas), market extent (the size of the market area over
which WTP is estimated), and the availability of substitute waters. The
model also takes into account important sociodemographic
characteristics, such as population and income, which vary spatially.
Table 12 in this preamble presents estimated household and total
annualized WTP value for water quality improvements following
attainment of the EPA's proposed WQS, based on a 3 percent discount
rate. The total annualized value of water quality improvements from
attainment of the proposed WQS is $112.8 million.
Table 12--Estimated Household and Total Annualized Willingness-to-Pay
(WTP) for Water Quality Improvements Under the EPA's Proposed Water
Quality Standards, Using a 3 Percent Discount Rate
------------------------------------------------------------------------
Total
Average annual annualized WTP
Average number of affected households WTP per (millions
(millions) household 2022$, 3%
(2022$) discount rate)
------------------------------------------------------------------------
14.96................................. $8.18 $112.8
------------------------------------------------------------------------
E. Conclusion
The United States Office of Management and Budget requires that for
``significant regulatory actions'' (as defined in Executive Order 12866
and as amended and reaffirmed by Executive Order 14094), that the EPA
conduct an economic analysis. While this proposed rulemaking was not
deemed significant, the EPA nonetheless conducted an economic analysis
to evaluate the potential costs and benefits associated with the WQS in
the EPA's proposed rule. For this proposed rulemaking, the EPA
determined that the potential benefits justify the potential costs. The
EPA estimates that the implementation of additional effluent treatment
controls at certain WWTPs could lead to $137.1 million in annualized
costs over 30 years (2022$, 3% discount rate). The EPA quantified
estimated non-market benefits through average annual household WTP for
water quality improvements. Annualized non-market benefits total $112.8
million per year over 30 years (2022$, 3% discount rate). The EPA's
monetary estimation of benefits does not account for benefits related
to protections for a critically endangered species (Atlantic Sturgeon),
increased housing values, or increased commercial fishing, among other
benefits. Therefore, the EPA's estimation of non-market benefits is
likely an underestimate of total benefits and thus total benefits could
potentially equal or exceed estimated total costs.
X. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 14094: Modernizing Regulatory Review
This action is not a significant regulatory action as defined in
Executive Order 12866, as amended by Executive Order 14094, and was
therefore not subject to a requirement for Executive Order 12866
review.
[[Page 88333]]
B. Paperwork Reduction Act (PRA)
This action does not impose any new information collection burden
under the PRA. OMB has previously approved the information collection
activities contained in the existing regulations and has assigned OMB
control number 2040-0049. While actions to implement these WQS, if
finalized, could entail additional paperwork burden, this action does
not directly contain any information collection, reporting, or record-
keeping requirements.
C. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. This
action will not impose any requirements on small entities. Small
entities, such as small businesses or small governmental jurisdictions,
are not directly regulated by this rulemaking.
EPA-promulgated WQS are implemented through various water quality
control programs including the NPDES program, which limits discharges
to navigable waters, except in compliance with a NPDES permit. CWA
section 301(b)(1)(C) and the EPA's implementing regulations at 40 CFR
122.44(d)(1) and 122.44(d)(1)(A) provide that all NPDES permits must
include any limits on discharges that are necessary to meet applicable
WQS. Thus, under the CWA, the EPA's promulgation of WQS establishes
standards that states implement through the NPDES permit process. While
states have discretion in developing discharge limits, those limits
``must control all pollutants or pollutant parameters (either
conventional, nonconventional, or toxic pollutants) which the Director
determines are or may be discharged at a level that will cause, have
the reasonable potential to cause, or contribute to an excursion above
any [s]tate water quality standard, including [s]tate narrative
criteria for water quality'' (40 CFR 122.44(d)(1)(i)).
As a result of this action, if finalized, the states of Delaware,
New Jersey, and Pennsylvania will need to ensure that permits they
issue include any limitations on discharges necessary to comply with
the WQS established in the final rule. In doing so, each state will
have several choices associated with permit writing. While each state's
implementation of the rule may ultimately result in new or revised
permit conditions for some dischargers, including small entities, the
EPA's action, by itself, does not impose any of these requirements on
small entities; in other words, these requirements are not self-
implementing.
D. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. The action imposes no enforceable duty on any state,
local, or Tribal governments or the private sector.
E. Executive Order 13132: Federalism
The EPA has concluded that this action does not have federalism
implications. It will not have substantial direct effects on the
states, on the relationship between the national government and the
states, or on the distribution of power and responsibilities among the
various levels of government. This rulemaking would not alter
Delaware's, New Jersey's, or Pennsylvania's considerable discretion in
implementing these WQS, nor would it preclude any of those states from
adopting revised WQS and submitting them to the EPA for review and
approval either before or after promulgation of the final rule. If the
states submit and the EPA approves revised WQS consistent with the CWA,
then the EPA would no longer be required to promulgate Federal WQS.
Consistent with the EPA's policy to promote communications between
the EPA and state and local governments, the EPA met with the states of
Delaware, New Jersey, and Pennsylvania and DRBC in the process of
developing this rulemaking to enable them to have meaningful input into
its development. During these discussions, the EPA explained the
scientific basis for the dissolved oxygen criteria to protect aquatic
life propagation in the specified zones of the Delaware River and the
overall timing of the Federal rulemaking effort. The EPA took these
discussions with the states into account during the drafting of this
rulemaking. The EPA specifically solicits comments on this proposed
action from state and local officials.
F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This action does not have Tribal implications as specified in
Executive Order 13175. This rulemaking will not affect federally
recognized Indian tribes in Delaware, New Jersey, or Pennsylvania
because the WQS would not apply to waters in Indian lands nor affect
Tribal interests. Thus, Executive Order 13175 does not apply to this
action.
G. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks
The EPA interprets Executive Order 13045 as applying only to those
regulatory actions considered significant under section 3(f)(1) of
Executive Order 12866 and that concern environmental health or safety
risks that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive order. Therefore, this action is not
subject to Executive Order 13045 because it does not concern an
environmental health risk or safety risk. Since this action does not
concern human health, the EPA's Policy on Children's Health also does
not apply.
H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use
This action is not a ``significant energy action'' because it is
not likely to have a significant adverse effect on the supply,
distribution, or use of energy. This action proposes to establish
Federal CWA aquatic life water quality criteria for specified zones of
the Delaware River under the jurisdiction of the states of Delaware,
New Jersey, and Pennsylvania.
I. National Technology Transfer and Advancement Act (NTTAA)
This rulemaking does not involve technical standards.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations and
Executive Order 14096: Revitalizing Our Nation's Commitment to
Environmental Justice for All
The information supporting this Executive order review is
summarized below and detailed in the associated document, Environmental
Justice Analysis for the Proposed Rule: Water Quality Standards to
Protect Aquatic Life in the Delaware River, which is available in the
docket for this proposed rule.
The EPA believes that the human health or environmental conditions
that exist prior to this proposed action result in or have the
potential to result in disproportionate and adverse human health or
environmental effects on communities with environmental justice (EJ)
concerns. For this EJ analysis, the EPA evaluated socioeconomic
characteristics of communities living near the relevant zones of the
Delaware River compared to communities living near other zones of the
mainstem
[[Page 88334]]
Delaware River. The relevant zones of the Delaware River border highly
urbanized areas, including cities such as Philadelphia and Wilmington.
Accordingly, the EPA's analysis accounts for the distinction between
urban and rural communities.\89\
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\89\ For this analysis, the EPA defines ``urban'' and ``rural''
using the Census Urban Areas designation. More information about the
Census classifications is available at https://www.census.gov/programs-surveys/geography/guidance/geo-areas/urban-rural.html.
---------------------------------------------------------------------------
The EPA obtained data from the United States Census Bureau's
American Community Survey (ACS) 5-year estimates for the years 2017-
2021 at the Census block group level to construct a set of eight
metrics for use in this analysis: (1) Black or African American, (2)
Asian, (3) Two or More Races, (4) Hispanic or Latino, (5) Limited
English Speaking Household, (6) Median Household Income, (7) Below 200%
of the Poverty Level, (8) Education Less than a High School Diploma or
Equivalent.\90\ Analysis of these eight socioeconomic metrics provides
insight into the spatial distribution and prevalence of certain
indicators of social vulnerability for communities near the Delaware
River.\91\
---------------------------------------------------------------------------
\90\ The EPA also considered populations who identify as
American Indian and Alaskan Native, Native Hawaiian and Other
Pacific Islander, and Some Other Race; however, in the Delaware
River watershed, these populations represent a very small fraction
(often less than 1%) of the community composition. Therefore, these
populations are not analyzed further in this EJ analysis.
\91\ In the 2016 Technical Guidance for Assessing Environmental
Justice in Regulatory Analysis, the EPA defined vulnerability as the
``physical, chemical, biological, social, and cultural factors that
result in certain communities and population groups being more
susceptible or more exposed to environmental toxins, or having
compromised ability to cope with and/or recover from such
exposure.'' For this EJ analysis, the EPA focused on social
vulnerability based on the metrics presented in table 3 of the
associated environmental justice analysis, which broadly cover
categories of race, ethnicity, linguistic isolation, income,
poverty, and education. These metrics provide insight into factors
that may affect the ability of communities near the Delaware River
to respond to environmental hazards or cope with reduced ecosystem
services that may result from inadequate water quality. Although
these socioeconomic metrics are relevant to communities living near
the Delaware River, they are not intended to be an exhaustive list
of all factors affecting community vulnerability. (Source: United
States Environmental Protection Agency. (2016). Technical Guidance
for Assessing Environmental Justice in Regulatory Analysis. https://www.epa.gov/sites/default/files/2016-06/documents/ejtg_5_6_16_v5.1.pdf.)
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The EPA extended a five-mile buffer from the specified zones to
capture communities living in close proximity to waters affected by the
EPA's proposed rule, if finalized.\92\ Similarly, the EPA extended a
five-mile buffer from other zones of the Delaware River to form a
comparison group. Given the large number of block groups located near
the mainstem Delaware River, communities are analyzed in groups, as
follows:
---------------------------------------------------------------------------
\92\ The EPA assumes that those living in Census block groups
that are within the five-mile buffer, and therefore closest to the
specified zones of the Delaware River, are most likely to be
directly affected by the proposed rule. However, this assumption
could underestimate directly affected communities and impact the
results of the proximity analysis. Accordingly, the EPA conducted a
sensitivity analysis using a ten-mile buffer and determined that
community composition was not particularly sensitive to the buffer
distance applied when comparing the results of the five-mile and
ten-mile buffer.
---------------------------------------------------------------------------
Delaware Urban Areas: Census block groups in urban areas
within five miles of the specified zones in Delaware.
New Jersey Urban Areas: Census block groups in urban areas
within five miles of the specified zones in New Jersey.
Pennsylvania Urban Areas: Census block groups in urban
areas within five miles of the specified zones in Pennsylvania.
Urban Comparison Group: Census block groups in urban areas
within five miles of the remainder of the mainstem Delaware River
(i.e., excluding block groups within five miles of the specified
zones).
Specified Zones Rural Areas: Census block groups in rural
areas within five miles of the specified zones in New Jersey.\93\
---------------------------------------------------------------------------
\93\ There are no rural areas within five miles of the specified
zones in Delaware or Pennsylvania.
---------------------------------------------------------------------------
Rural Comparison Group: Census block groups in rural areas
within five miles of the remainder of the mainstem Delaware River
(i.e., excluding block groups within five miles of the specified
zones).
The EPA aggregated data across multiple block groups using aerial
apportionment and a population-weighted mean approach to ensure that
block groups with larger or smaller populations were accounted for
proportionally to their size. This calculation relies on an assumption
that households are evenly distributed within each block group. For
Median Household Income, the EPA aggregated data across multiple block
groups using a linear interpolation calculation.
The results of the urban and rural proximity analyses differed
significantly. Urban communities in Pennsylvania near the specified
zones surpassed the comparison group average (or were less than the
comparison group for Median Household Income) for all eight
socioeconomic metrics. Notably, urban communities in Pennsylvania near
the specified zones are over 1.7 times more likely to identify as Black
or African American, 1.7 times more likely to live below twice the
poverty level, and have $23,000 lower median household income when
compared to urban communities near the remainder of the mainstem river.
Urban communities within five miles of the specified zones in all three
states had lower income and higher poverty rates than the comparison
group. Urban communities in Delaware near the specified zones also had
a higher percentage of the population identify as Black or African
American than the comparison group, while urban communities in New
Jersey had a higher percentage of the population that identifies as
Hispanic or Latino and a greater percentage with education less than a
high school degree than the comparison group. Therefore, urban
communities near the specified zones--especially in Pennsylvania--
exhibited differences in socioeconomic community characteristics
compared to other urban communities near the Delaware River.
On the other hand, rural communities near the specified zones did
not greatly differ from rural communities near other parts of the
mainstem river. While rural communities near the specified zones did
exceed the comparison group average for four metrics (Black or African
American, Asian, Two or More Races, and Limited English Speaking
Household), the differences were always less than three percentage
points. Therefore, the EPA could not conclude that rural communities
near the specified zones were any more or less socially vulnerable
compared to other rural communities near the mainstem Delaware River.
While neither the urban nor the rural proximity analyses directly
indicate which communities may be experiencing potential EJ concerns,
they provide insight into community composition surrounding an
environmental resource. In general, the Delaware River has had two
contrasting areas of water quality for decades. In the relevant zones,
water quality for aquatic life has been significantly worse than in the
other zones of the river.\94\ Urban areas near these zones, especially
in Pennsylvania, contain communities that are likely more socially
vulnerable than urban communities that live near other zones of the
Delaware River, which have better water quality. This trend in water
quality and dissolved oxygen across the watershed, coupled with the
corresponding differences in socioeconomic community composition,
reveals a potential inequitable
[[Page 88335]]
distribution of an environmental resource and access to clean surface
waters within a single watershed.\95\
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\94\ Delaware River Basin Commission (2022a).
\95\ In this analysis, the EPA is not implying causality between
poor water quality and socioeconomic factors.
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The EPA believes that this action would be likely to reduce
existing disproportionate and adverse effects on communities with EJ
concerns. Specifically, the EPA identified an inequitable distribution
of an environmental resource where communities with environmental
justice concerns have inequitable access to clean surface waters that
support CWA section 101(a)(2) goals for aquatic life. The EPA's
proposed rule, if finalized and implemented, could help to lessen this
inequitable distribution of an environmental resource by ensuring that
WQS to protect aquatic life in the specified zones of the Delaware
River meet the objectives of the CWA.
In addition to the proximity analysis, the EPA evaluated the
potential distribution of costs associated with the proposed rule under
the implementation (policy) scenario described in section IX of this
preamble and further detailed in the EPA's associated document,
Economic Analysis for the Proposed Rule: Water Quality Standards to
Protect Aquatic Life in the Delaware River. For this analysis, the EPA
selected Philadelphia as a case study based on the results of the
proximity analysis and the large share of total estimated costs
potentially incurred by the Philadelphia Water Department (PWD)
compared to other WWTPs.
The EPA used two methods to assess the potential financial impact
to Philadelphia households resulting from costs associated with the
proposed rule. First, the EPA calculated household burden by
quantifying the potential increase to consumer water and wastewater
bills and calculating the percentage of median household income spent
on water bills with and without costs from additional wastewater
treatment plant controls. Second, the EPA examined existing water rate
structures in Philadelphia and customer assistance programs to identify
possible ways in which the affected municipalities could adjust rates
to lessen the financial burden on low-income households.
To determine household burden, the EPA analyzed how annual water
and wastewater bills might change if costs associated with additional
wastewater treatment plant controls at PWD facilities are passed on to
households through increased water bills.\96\ The EPA analyzed the
financial impact to households if costs were passed on to residential
households in proportion to the estimated wastewater flow attributed to
residential households.\97\ DRBC estimates that approximately 15% of
the flow to PWD is attributable to residential sources while 85% is
attributable to non-residential sources.\98\ Therefore, the EPA
calculated household burden assuming 15% of the costs associated with
additional wastewater treatment plant controls would be spread evenly
among Philadelphia households. Under this assumption the additional
annual cost per household is $18.07, which would equate to $1.50 per
household per month.\99\ For this analysis, the EPA analyzed household
burden using the Residential Indicator in the EPA's 2023 Clean Water
Act Financial Capability Assessment Guidance \100\ and determined that
while the costs associated with the proposed rule are not expected to
substantially impact household burden under this scenario, water bills
still have the potential to be placing a high burden on a third of
Philadelphia's households. However, the actual financial burden faced
by households depends on many factors, including customer assistance
programs.
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\96\ Residents in PWD's service area pay a single bill that
covers both water and wastewater charges; for this analysis, the EPA
uses the term ``water bill'' to refer to the single bill covering
water and wastewater charges.
\97\ The EPA also analyzed a conservative scenario in which 100%
of costs are passed on to residential households. Results of this
scenario are available in the associated document, Environmental
Justice Analysis for the Proposed Rule: Water Quality Standards to
Protect Aquatic Life in the Delaware River.
\98\ Delaware River Basin Commission. (2022c). Social and
Economic Factors Affecting the Attainment of Aquatic Life Uses in
the Delaware River Estuary. September 2022 Draft. https://www.nj.gov/drbc/library/documents/AnalysisAttainability/SocialandEconomicFactors_DRAFTsept2022.pdf.
\99\ As of September 1, 2023, the monthly water bill for a
typical residential consumer in Philadelphia is $74.81, which
equates to $897.72 annually. Source: Philadelphia Water Department.
Rate Changes Effective September 2023. Web page, accessed September
26, 2023. https://water.phila.gov/drops/new-rate-information-effective-september-2023/.
\100\ United States Environmental Protection Agency. (2023).
Clean Water Act Financial Capability Assessment Guidance. Document
ID: 800b21001. February 2023. https://www.epa.gov/system/files/documents/2023-01/cwa-financial-capability-assessment-guidance.pdf.
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In July 2017, Philadelphia became the first to implement an income-
based alternative water rate structure through creation of the Tiered
Assistance Program (TAP). This program is structured based on household
income relative to the Federal poverty level such that monthly bills
are capped at 2%, 2.5%, 3%, and 4% of monthly income for consumers
whose income is 0-50%, >50-100%, >100-150%, and >150% of the Federal
poverty level, respectively.\101\ TAP discounts are offset by a
surcharge added to the water bill of non-TAP customers.
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\101\ City of Philadelphia. (2023). Annual Report to the Mayor
on the Tiered Assistance Program (TAP). Department of Revenue. March
31, 2023. https://www.phila.gov/media/20230526113411/Tiered-Assistance-Program-TAP-2022-annual-report.pdf.
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For illustrative purposes, the EPA analyzed how the TAP rate
structure might apply to eligible low-income consumers with water bills
that include 15% of the costs associated with additional PWD wastewater
treatment plant controls.\102\ Under the TAP rate structure, a three-
person household with income at or below the poverty level would have
annual savings of at least $294. These savings are particularly
significant for households whose income is half the poverty level or
below. For example, a household at 50% of the poverty level would see
savings of $667.
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\102\ The EPA does not have the necessary data to calculate a
per household surcharge that could increase water bills for higher-
income customers, nor did the EPA include other assistance programs
in this calculation.
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However, the effectiveness of the TAP rate structure depends in
large part on participation by eligible households. When Philadelphia
launched TAP in 2017, it was estimated that around 60,000 consumers
would be eligible for the program.\103\ However, as of December 2022,
only 14,712 households were actively participating in TAP.\104\ Equally
problematic as low participation rates are the high attrition rates of
TAP participants. In 2022, 9,496 participants defaulted from TAP due to
a failure to recertify for the program. Of those who defaulted, 75%
percent did not respond to the city's request for recertification.\105\
Thus, even though Philadelphia enrolled 10,405 participants in 2022,
the high attrition rate in the program prevents meaningful increases in
participation. Philadelphia continues outreach efforts to raise
awareness about TAP; \106\ however, this large gap in participation
indicates that
[[Page 88336]]
the full potential of the program is likely not being realized.
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\103\ City of Philadelphia. (2017). Philadelphia Launches New,
Income-Based, Tiered Assistance Program. Press Release. Office of
the Mayor. June 20, 2017. https://www.phila.gov/press-releases/mayor/philadelphia-launches-new-income-based-tiered-assistance-program/.
\104\ City of Philadelphia. (2023). Annual Report to the Mayor
on the Tiered Assistance Program (TAP). Department of Revenue. March
31, 2023. https://www.phila.gov/media/20230526113411/Tiered-Assistance-Program-TAP-2022-annual-report.pdf.
\105\ Id.
\106\ Id.
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Based on the structure of TAP and the current low participation
rates, low-income communities are not necessarily protected from high
water bills and increasing water rates. The way the program is
designed, non-TAP customers subsidize the discounts applied to TAP
customers. When there is high participation, the majority of program
costs are borne by higher income households and participating low-
income households are protected from high water bills and increasing
water rates (including potential rate increases to offset costs
associated with additional wastewater treatment plant technologies).
With low-participation rates, a higher proportion of low-income
households are paying the TAP surcharge and face higher water rates,
thus placing an undue burden on low-income households not participating
in the program.
In theory, costs associated with the EPA's proposed rule--if
partially or fully passed on to residential consumers--should not
impact the lowest income households in Philadelphia, assuming high
participation in TAP. However, the current low participation rates in
TAP indicate that some low-income communities are likely burdened by
high water bills and could potentially indirectly bear costs associated
with the EPA's proposed rule. Although Philadelphia's TAP is
innovative, additional work to increase participation (through
increased enrollment and decreased attrition rates) can further advance
water affordability and protect low-income households.
The example of Philadelphia's TAP illustrates how an income-based
rate structure can potentially have a measurable impact on low-income
communities. Municipalities potentially affected by the EPA's proposed
rule might consider holistic ways to advance water affordability, which
can include adoption of alternative water rate structures and
assistance programs that lower water bills for low-income households.
There are several considerations for municipalities if choosing to
implement a program similar to TAP in Philadelphia.\107\ An income-
based rate structure, such as Philadelphia's TAP, might be most
effective for utilities with larger service areas and higher income
disparities for households within the service area. When a utility has
a large customer base, it allows the utility to distribute any
surcharges (to offset lost revenue) among many households.\108\ In
theory, this redistribution of costs means that the per household
surcharge can be small and affect higher income households who might be
less socially vulnerable. In addition, the effectiveness of an income-
based rate structure hinges on the participation rate of low-income
communities. Municipalities seeking to implement a similar program
should consider practices to encourage high enrollment and high
retention rates among qualified households. Such practices could
include automatically enrolling households who are concurrently on
other assistance programs (such as SNAP) or ensuring a user-friendly
process for recertification of eligibility, if applicable. By
thoughtfully and strategically advancing water affordability programs,
municipalities can work towards ensuring that socially vulnerable
communities are not overburdened by expensive water bills.
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\107\ Mack, E.A., Wrase, S., Dahme, J., Crosby, S.M., Davis, M.,
Wright, M., & Muhammad, R. (2020). An Experiment in Making Water
Affordable: Philadelphia's Tiered Assistance Program (TAP). Journal
of the American Water Resources Association, 56(3), 431-449. https://doi.org/10.1111/1752-1688.12830.
\108\ Id.
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List of Subjects in 40 CFR Part 131
Environmental protection, Indians-lands, Intergovernmental
relations, Reporting and recordkeeping requirements, Water pollution
control.
Michael S. Regan,
Administrator.
For the reasons set forth in the preamble, the EPA proposes to
amend 40 CFR part 131 as follows:
PART 131--WATER QUALITY STANDARDS
0
1. The authority citation for part 131 continues to read as follows:
Authority: 33 U.S.C. 1251 et seq.
0
2. Add Sec. 131.XX to read as follows:
Sec. 131.XX Water quality standards to protect aquatic life in the
Delaware River.
(a) Scope. (1) The designated use in paragraph (b) of this section
applies to river miles 108.4 to 70.0 of the Delaware River for the
states of New Jersey and Pennsylvania.
(2) The aquatic life criteria in paragraph (c) of this section
apply to river miles 108.4 to 70.0 of the Delaware River for the states
of Delaware, New Jersey, and Pennsylvania.
(b) Aquatic life designated use. The aquatic life designated use is
protection and propagation of resident and migratory aquatic life.
(c) Dissolved oxygen criteria. The applicable dissolved oxygen
criteria are shown in table 1 to this paragraph (c).
Table 1 to Paragraph (c)--Dissolved Oxygen Criteria
----------------------------------------------------------------------------------------------------------------
Magnitude
Season (percent oxygen Duration Exceedance frequency
saturation)
----------------------------------------------------------------------------------------------------------------
Spawning and Larval Development (March 66 Daily Average............. 10% (12 Days Cumulative).
1-June 30).
Juvenile Development (July 1-October 66 Daily Average............. 10% (12 Days Cumulative).
31).
74 Daily Average............. 50% (61 Days Cumulative).
Overwintering (November 1-February 28/ 66 Daily Average............. 10% (12 Days Cumulative).
29).
----------------------------------------------------------------------------------------------------------------
(d) Applicability. (1) The aquatic life designated use in paragraph
(b) of this section applies concurrently with other applicable
designated uses in New Jersey and Pennsylvania for river miles 108.4 to
70.0 of the Delaware River.
(2) The dissolved oxygen aquatic life water quality criteria in
paragraph (c) of this section are the applicable dissolved oxygen
criteria in Delaware, New Jersey, and Pennsylvania for river miles
108.4 to 70.0 of the Delaware River and apply concurrently with
applicable water quality criteria for other parameters.
(3) The designated use and criteria established are subject to
Delaware's, New Jersey's, and Pennsylvania's general rules of
applicability in the same way and to the same extent as are other
federally promulgated and state-adopted water quality standards in
those states.
[FR Doc. 2023-27758 Filed 12-20-23; 8:45 am]
BILLING CODE 6560-50-P
