Indiana Administrative Code
Title 327 - WATER POLLUTION CONTROL DIVISION
Article 5 - INDUSTRIAL WASTEWATER PRETREATMENT PROGRAMS AND NPDES
Rule 2 - Basic NPDES Requirements
Section 2-11.4 - Great Lakes system dischargers total maximum daily loads; wasteload allocations for point sources; load allocations for nonpoint sources; preliminary wasteload allocations
Universal Citation: 327 IN Admin Code 2-11.4
Current through September 18, 2024
Authority: IC 13-14-8; IC 13-14-9; IC 13-15-1-2; IC 13-15-2-1; IC 13-18-3
Affected: IC 13-11-2; IC 13-18-4-7; IC 13-18-4-8
Sec. 11.4.
(a) This subsection applies to the establishment of TMDLs for all pollutants and pollutant parameters in the Great Lakes system. Where specified, the following conditions also apply to WLAs calculated in the absence of TMDLs and to preliminary WLAs:
(1) At a minimum, TMDLs
shall be established in accordance with the listing and priority setting
process established in Section 303(d) of the Clean Water Act (CWA) and at
40
CFR 130.7. Where water quality standards
cannot be attained immediately, TMDLs must reflect reasonable assurances that
water quality standards will be attained in a reasonable period of time. TMDLs
may be based on attaining water quality standards over a period of time, with
specific controls on individual sources being implemented in stages.
Determining the reasonable period of time in which water quality standards will
be met is a case-specific determination considering a number of factors,
including, but not limited to, the following:
(A) Receiving water
characteristics.
(B) Persistence,
behavior, and ubiquity of pollutants of concern.
(C) Type of remediation activities
necessary.
(D) Available regulatory
and nonregulatory controls.
(E)
Requirements for attainment of water quality standards.
(2) An assessment and remediation plan that
the commissioner has certified as meeting the requirements of this section
pertaining to TMDLs and public participation requirements applicable to TMDLs,
and that has been approved by EPA as meeting those requirements under
40 CFR
130.6, may be used in lieu of a TMDL for
purposes of this section. Assessment and remediation plans under this section
may include, but are not limited to, the following:
(A) Lakewide Management Plans.
(B) Remedial Action Plans.
(C) State Water Quality Management Plans.
Also, any part of an assessment and remediation plan that also satisfies one (1) or more requirements under Section 303(d) of the CWA or implementing regulations may be incorporated by reference into a TMDL as appropriate. Assessment and remediation plans under this section shall be tailored to the level of detail and magnitude for the watershed and pollutant being assessed.
(3) TMDLs, WLAs calculated in the absence of
a TMDL, and preliminary WLAs must ensure attainment of applicable water quality
standards including all numeric and narrative water quality criteria set forth
in
327 IAC
2-1.5-8 and
327
IAC 2-1.5-16, and Tier I criteria and Tier II values
established under
327 IAC
2-1.5-11 through
327
IAC 2-1.5-16.
(4) If a discharge contains one (1) or more
substances for which a TMDL, WLA calculated in the absence of a TMDL, or
preliminary WLA was based on an HCC, HCV, HNC, or HNV, human health shall be
protected from the potential adverse additive effects of mixtures of substances
in an effluent in accordance with the following procedures:
(A) If an effluent for a particular
discharger contains more than one (1) substance for which an HCC exists or for
which an HCC or an HCV can be calculated, the additivity of the mixture of
carcinogens shall be addressed as follows:
(i)
Except as provided in item (ii), the TMDL, WLA calculated in the absence of a
TMDL, or preliminary WLA based on an HCC or HCV shall be established to protect
against additive effects possibly associated with simultaneous multiple
chemical human exposure to carcinogens such that the following condition is
met:
| Where: | C | = | The adjusted TMDL, WLA calculated in the absence of a TMDL, or preliminary WLA concentration of each separate carcinogen that shall be used in the calculation of reasonable potential in section 11.5 of this rule and water quality-based effluent limitations (WQBELs) in section 11.6 of this rule. |
| WLA | = | The TMDL, WLA calculated in the absence of a TMDL, or preliminary WLA concentration based on the HCC or HCV for each respective carcinogen. | |
| n | = | Number of WLAs based on an HCC or HCV. |
(ii)
Notwithstanding item (i):
(AA) the
commissioner may consider, upon submission of the discharger, the use of an
alternate, scientifically-based, procedure for ensuring the aggregate risk of
the mixture of carcinogens remains below one (1) in one hundred thousand
(100,000); or
(BB) if information
is available to the commissioner demonstrating that available scientific
information does not support the assumption of additivity, the TMDL, WLA
calculated in the absence of a TMDL, or preliminary WLA shall not be adjusted
for each such substance.
(B) If an effluent for a particular
discharger contains more than one (1) substance for which an HNC exists or for
which an HNC or HNV can be calculated, the additivity of the mixture of
substances shall be addressed as follows:
(i)
The incremental adverse effect of each substance shall be assumed to not be
additive except as provided in item (ii).
(ii) If scientific information available to
the commissioner demonstrates that the adverse effects of the components are
additive, the TMDL, WLA calculated in the absence of a TMDL, or preliminary WLA
based on an HNC or HNV for each additive noncarcinogenic substance shall be
established to protect against additive effects possibly associated with
simultaneous multiple chemical human exposure such that the following condition
is met:
| Where: | N | = | The adjusted TMDL, WLA calculated in the absence of a TMDL, or preliminary WLA concentration of each separate additive noncarcinogenic substance that shall be used in the calculation of reasonable potential in section 11.5 of this rule and WQBELs in section 11.6 of this rule. |
| WLA | = | The TMDL, WLA calculated in the absence of a TMDL, or preliminary WLA concentration based on the HNC or HNV for each respective additive noncarcinogenic substance. | |
| n | = | Number of WLAs based on an HNC or HNV for additive noncarcinogenic substances. |
(C) Notwithstanding clauses (A) and (B), the
toxicity equivalency factors (TEFs) and bioaccumulation equivalency factors
(BEFs) for the chlorinated dibenzo-p-dioxins (CDDs) and chlorinated
dibenzofurans (CDFs) shall be accounted for as follows:
(i) The TEFs and BEFs in Table 11.4-1 in item
(iv) shall be used when calculating a 2,3,7,8-TCDD toxicity equivalence
concentration in effluent to be used when implementing both HNC and HCC. The
chemical concentration of each CDDs and CDFs in effluent shall be converted to
a 2,3,7,8-TCDD toxicity equivalence concentration in effluent by:
(AA) multiplying the chemical concentration
of each CDDs and CDFs in the effluent by the appropriate TEF in Table 11.4-1 in
item (iv);
(BB) multiplying each
product from subitem (AA) by the BEF for each CDDs and CDFs in Table 11.4-1 in
item (iv); and
(CC) adding all
final products from subitem (BB).
(ii) The equation for calculating the
2,3,7,8-TCDD toxicity equivalence concentration in effluent is:
| Where: | (TEC)tcdd | = | 2,3,7,8-TCDD toxicity equivalence concentration in effluent. |
| (C)x | = | Concentration of total chemical x in effluent. | |
| (TEF)x | = | TCDD toxicity equivalency factor for x. | |
| (BEF)x | = | TCDD bioaccumulation equivalency factor for x. |
(iii) The 2,3,7,8-TCDD toxicity equivalence
concentration in effluent shall be used when developing TMDLs, WLAs in the
absence of a TMDL, or preliminary WLAs under this section.
(iv) The following values shall be used for
TEFs and BEFs for CDDs and CDFs:
| Table 11.4-1 | ||
| Toxicity Equivalency Factors (TEF) and Bioaccumulation Equivalency Factors (BEF) for CDDs and CDFs | ||
| Congener | TEF | BEF |
| 2,3,7,8-TCDD | 1.0 | 1.0 |
| 1,2,3,7,8-PeCDD | 0.5 | 0.9 |
| 1,2,3,4,7,8-HxCDD | 0.1 | 0.3 |
| 1,2,3,6,7,8-HxCDD | 0.1 | 0.1 |
| 1,2,3,7,8,9-HxCDD | 0.1 | 0.1 |
| 1,2,3,4,6,7,8-HpCDD | 0.01 | 0.05 |
| OCDD | 0.001 | 0.01 |
| 2,3,7,8-TCDF | 0.1 | 0.8 |
| 1,2,3,7,8-PeCDF | 0.05 | 0.2 |
| 2,3,4,7,8-PeCDF | 0.5 | 1.6 |
| 1,2,3,4,7,8-HxCDF | 0.1 | 0.08 |
| 1,2,3,6,7,8-HxCDF | 0.1 | 0.2 |
| 2,3,4,6,7,8-HxCDF | 0.1 | 0.7 |
| 1,2,3,7,8,9-HxCDF | 0.1 | 0.6 |
| 1,2,3,4,6,7,8-HpCDF | 0.01 | 0.01 |
| 1,2,3,4,7,8,9-HpCDF | 0.01 | 0.4 |
| OCDF | 0.001 | 0.02 |
(5) TMDLs shall include WLAs for point
sources and LAs for nonpoint sources, including natural background, such that
the sum of these allocations is not greater than the loading capacity of the
water for the pollutant addressed by the TMDL, minus the sum of a specified
margin of safety (MOS) and any capacity reserved for future growth. The
components of the TMDL are as follows:
(A)
Nonpoint source LAs that shall be based on any of the following:
(i) Existing pollutant loadings if changes in
loadings are not reasonably anticipated to occur.
(ii) Increases in pollutant loadings that are
reasonably anticipated to occur.
(iii) Anticipated decreases in pollutant
loadings if such decreased loadings are technically feasible and are reasonably
anticipated to occur within a reasonable time period as a result of
implementation of BMPs or other load reduction measures. In determining whether
anticipated decreases in pollutant loadings are technically feasible and can
reasonably be expected to occur within a reasonable period of time, technical
and institutional factors shall be considered. These decisions are
case-specific and should reflect the particular TMDL under
consideration.
(iv) Where
appropriate and where sufficient data are available, contributions to the water
column from sediments inside and outside of any applicable mixing
zones.
(v) Where appropriate and
where sufficient data are available, nonpoint source discharges resulting from
wet weather events.
Monitoring data for these LAs shall be collected and analyzed in order to validate the TMDL's assumptions, to verify anticipated load reductions, to evaluate the effectiveness of controls being used to implement the TMDL, and to revise the WLAs and LAs as necessary to ensure that water quality criteria shall be achieved within the time period established in the TMDL.
(B) Each
TMDL shall include an MOS sufficient to account for technical uncertainties in
establishing the TMDL and shall describe the manner in which the MOS is
determined and incorporated into the TMDL. The MOS may be provided by leaving a
portion of the loading capacity unallocated or by using conservative modeling
assumptions to establish WLAs and LAs. If a portion of the loading capacity is
left unallocated to provide an MOS, the amount left unallocated shall be
described. If conservative modeling assumptions are relied on to provide an
MOS, the specific assumptions providing the MOS shall be identified.
(C) TMDLs may include reserved allocations of
loading capacity to accommodate future growth and additional sources. Where
such reserved allocations are not included in a TMDL, any increased loadings of
the pollutant for which the TMDL was developed that are due to a new or
expanded discharge shall not be allowed unless the TMDL is revised in
accordance with these procedures to include an allocation for the new or
expanded discharge.
(D) The sum of
the WLAs is the portion of the loading capacity not assigned to nonpoint
sources including background, or to an MOS, or reserved for future growth.
Where appropriate and where sufficient data are available, WLAs shall also be
developed for point source discharges resulting from wet weather events. Upon
reissuance, NPDES permits for these point sources must include effluent
limitations consistent with WLAs in EPA-approved or EPA-established
TMDLs.
(6) If separate
TMDLs are prepared for different segments of the same watershed, and the
separate TMDLs each include WLAs for the same pollutant for one (1) or more of
the same point sources, then WQBELs for that pollutant for the point sources
shall be consistent with the most stringent of those WLAs in order to ensure
attainment of all applicable water quality standards.
(7) TMDLs shall be sufficiently stringent so
as to prevent accumulation of the pollutant of concern in sediments to levels
injurious to designated or existing uses, human health, wildlife, and aquatic
life.
(8) The representative
background concentration of pollutants shall be established in accordance with
this section to develop TMDLs, WLAs calculated in the absence of a TMDL, and
preliminary WLAs. Background loadings may be accounted for in a TMDL through an
allocation to a single background category or through individual allocations to
the various background sources as follows:
(A)
As used in this subsection, "background" represents all loadings resulting from
the following:
(i) Flow from upstream waters
into the specified watershed, waterbody, or waterbody segment for which a TMDL,
WLA in the absence of a TMDL, or preliminary WLA for the purpose of determining
the need for a WQBEL is being developed.
(ii) Atmospheric deposition or sediment
release or resuspension.
(iii)
Chemical reactions occurring within the watershed, waterbody, or waterbody
segment.
(B) When
determining what available data are acceptable for use in calculating
background, the commissioner shall use best professional judgment, including
consideration of the sampling location and the reliability of the data through
comparison to reported analytical detection levels. Pollutant degradation and
transport information may be considered when utilizing pollutant loading data.
Where limited or no acceptable data exist, the commissioner may require the
permittee to supply the necessary data. Best professional judgment shall be
used to select the one (1) data set that most accurately reflects or estimates
background concentrations when data in more than one (1) of the following data
sets or categories exist:
(i) Acceptable
available water column data.
(ii)
Water column concentrations estimated through use of acceptable available caged
or resident fish tissue data.
(iii)
Water column concentrations estimated through use of acceptable available or
projected pollutant loading data.
(C) The representative background
concentration for a substance in the specified watershed, waterbody, or
waterbody segment shall be established as follows:
(i) If all the values in the data set
selected in clause (B) are at or above the LOD, then the background
concentration is the geometric mean of that data set.
(ii) If the data set consists of values above
and below the LOD, the following procedure shall be used to determine the
representative background concentration:
(AA)
Each value in the data set with a value less than the LOD (nondetect) shall be
assigned the value (V). The geometric mean of this adjusted data set is the
representative background concentration. The value (V) is determined as
follows:
(BB) If
information is available that indicates an alternate methodology for evaluating
the data set would result in a background concentration more representative of
actual conditions, this alternative methodology may be used in place of the
methodology contained in subitem (AA) upon approval of the
commissioner.
(iii) When
all of the acceptable available data in a data set or category, such as water
column, caged or resident fish tissue, or pollutant loading data, are below the
LOD for a substance, and the most sensitive approved analytical method
available for that substance was used, then all the data for that pollutant in
that data set shall be assumed to be zero (0).
(iv) Notwithstanding items (i) through (iii),
the representative background concentration of whole effluent toxicity (WET)
shall be assumed to be zero (0) unless data are available that indicates that
the discharge of the WET and any background WET are additive.
(9) The effluent flow
used to develop TMDLs, WLAs calculated in the absence of a TMDL, and
preliminary WLAs shall be determined as follows:
(A) For municipal, semipublic, and other
sanitary or domestic wastewater discharges, the average design flow of the
treatment facility shall be used.
(B) For industrial dischargers, the highest
monthly average flow from the previous two (2) years of monitoring shall be
used.
(C) Notwithstanding clauses
(A) and (B), an alternate effluent flow value may be used, upon approval by the
commissioner, if the discharger provides flow data that supports the alternate
value (such as when a TMDL or WLA is calculated for wet weather conditions as
provided in section 11.6(g)(4) of this rule). This flow data shall be included
with the application for a new permit, a renewal of an existing permit, or with
a request for modification of an existing permit, or when requested by the
commissioner.
(D) TMDLs, WLAs
calculated in the absence of a TMDL, and preliminary WLAs shall indicate the
point source effluent flows used in the analyses.
(10) The portion of the receiving waterbody
allocated for mixing for TMDLs, WLAs calculated in the absence of a TMDL, and
preliminary WLAs shall be determined in accordance with subsection
(b).
(11) TMDLs, WLAs in the
absence of a TMDL, and preliminary WLAs shall be based on the assumption that a
pollutant does not degrade. However, the commissioner may take into account
degradation of the pollutant if each of the following conditions are met:
(A) Scientifically valid field studies or
other relevant information demonstrate that degradation of the pollutant is
expected to occur under the full range of environmental conditions expected to
be encountered.
(B) Scientifically
valid field studies or other relevant information addresses other factors that
affect the level of pollutants in the water column, including, but not limited
to, the following:
(i) Resuspension of
sediments.
(ii) Chemical
speciation.
(iii) Biological and
chemical transformation.
(C) Notwithstanding clauses (A) and (B),
TMDLs, WLAs in the absence of a TMDL, and preliminary WLAs conducted for
chlorine and WET shall be based on the assumption that the parameter does
degrade unless data for the waterbody are available indicating
otherwise.
(12) As used
in this section, "loading capacity" refers to the greatest amount of loading
that a water can receive without violating water quality standards. The loading
capacity is initially calculated at the farthest downstream location in the
watershed drainage basin. The maximum allowable loading consistent with the
attainment of each applicable numeric criterion or value for a given pollutant
is determined by multiplying the applicable criterion or value by the flow at
the farthest downstream location in the tributary basin at the design flow
condition described under subsection (b) and by using appropriate conversion
factors. This loading is then compared to the loadings at sites within the
basin to assure that applicable numeric criteria or values for a given
pollutant are not exceeded at all applicable sites. The lowest load is then
selected as the loading capacity.
(13) The ambient water quality
characteristics used to develop TMDLs, WLAs calculated in the absence of a
TMDL, and preliminary WLAs shall be determined as follows:
(A) For ammonia (as N), chloride, metals
dependent on hardness, and pentachlorophenol, the appropriate water quality
characteristics shall be obtained at a location downstream of the point of
discharge, or for Lake Michigan, outside the applicable mixing zone and shall
be determined as follows:
(i) For ammonia (as
N), the seventy-fifth percentile of the pH and temperature. If a seasonal TMDL,
WLA calculated in the absence of a TMDL, or preliminary WLA is developed for
ammonia, the pH and temperature data shall be obtained from the appropriate
seasonal period.
(ii) For chloride,
the fiftieth percentile of the hardness and sulfate.
(iii) For metals dependent on hardness, the
fiftieth percentile of the hardness.
(iv) For pentachlorophenol, the fiftieth
percentile of the pH.
(B) If any of the data required under clause
(A) are not available for the waterbody, the data shall either be obtained from
similar nearby streams or the permittee will be required to obtain the
necessary data. For discharges to Lake Michigan, data from Lake Michigan shall
be required.
(C) The use of the
data required in clause (A) is intended to determine values of those water
quality characteristics that are representative of those characteristics at
design conditions. If it is demonstrated that an alternate method of
determining these characteristics for a specific receiving waterbody would
result in values more representative of the characteristics at design
conditions, then this alternate method may be used to determine the water
quality characteristics.
(b) The following requirements shall be applied in establishing the portion of the receiving waterbody allocated for mixing for TMDLs, WLAs in the absence of TMDLs, and preliminary WLAs:
(1) The following procedures shall be used to
establish the portion of the receiving waterbody allocated for mixing for
TMDLs, WLAs in the absence of TMDLs, and preliminary WLAs for a BCC:
(A) For purposes of this subsection, new and
existing discharges are determined as follows:
(i) New discharges are defined as:
(AA) discharges from new Great Lakes
dischargers; or
(BB) new or
expanded discharges from an existing Great Lakes discharger.
(ii) Existing discharges are
defined as all discharges of BCCs not included in item (i).
(B) There shall be no mixing zone
available for a new discharge of a BCC to the Great Lakes system. WLAs
established through TMDLs, WLAs in the absence of TMDLs, and preliminary WLAs
for a new discharge of a BCC shall be set equal to the most stringent
applicable water quality criteria or values for the BCC.
(C) A mixing zone may be allocated for a BCC
for an existing discharge to the Great Lakes system under subdivisions (2) and
(3) until January 1, 2004, except for a discharge into the open waters of Lake
Michigan. WLAs established through TMDLs, WLAs established in the absence of
TMDLs, and preliminary WLAs for all discharges, both new and existing, into the
open waters of Lake Michigan shall be set equal to the most stringent
applicable water quality criteria or values for the BCC.
(D) Except as provided in clauses (E) and
(F), NPDES permits shall not authorize mixing zones for existing discharges of
a BCC to the Great Lakes system after January 1, 2004. After January 1, 2004,
WLAs established through TMDLs, WLAs established in the absence of TMDLs, and
preliminary WLAs for all discharges of a BCC to the Great Lakes system shall be
set equal to the most stringent applicable water quality criteria or values for
the BCC.
(E) The commissioner may
grant mixing zones for any existing discharge of a BCC to the Great Lakes
system beyond the date specified in clause (D) where it can be demonstrated, on
a case-by-case basis, that failure to grant a mixing zone would preclude water
conservation measures that would lead to the overall load reduction of the BCC,
even though higher concentrations of the BCC occur in the effluent. Such mixing
zones must also be consistent with subdivisions (2) and (3).
(F) The commissioner may grant mixing zones,
consistent with subdivisions (2) and (3), beyond the date specified in clause
(D) for any existing discharge of a BCC to the Great Lakes system upon the
request of a discharger subject to the following limited circumstances:
(i) The commissioner determines the
following:
(AA) The discharger is in
compliance with and will continue to implement all applicable technology-based
treatment and pretreatment requirements of Sections 301, 302, 304, 306, 307,
401, and 402 of the CWA, and is in compliance with its existing NPDES WQBELs,
including those based on a mixing zone.
(BB) The discharger has reduced and will
continue to reduce the loading of the BCC for which a mixing zone is requested
to the maximum extent possible.
(ii) In making the determination in item (i),
the commissioner shall consider the following information submitted by the
discharger:
(AA) The availability,
feasibility, cost effectiveness, and environmental benefits of additional
controls or pollution prevention measures for reducing and ultimately
eliminating the BCC for that discharger, including those used by similar
dischargers. As used in this item, "pollution prevention" has the meaning set
forth in the federal Pollution Prevention Act of 1990 (
42 U.S.C.
13101 et seq.).
(BB) Whether the discharger or affected
communities will suffer unreasonable economic effects if the mixing zone is
eliminated.
(CC) The extent to
which the discharger will implement an ambient monitoring plan to ensure
compliance with water quality criteria at the edge of any authorized mixing
zone or to ensure consistency with any applicable TMDL or such other strategy
consistent with this section.
(DD)
Other information the commissioner deems appropriate.
(iii) Any exceptions to the mixing zone
elimination provision for an existing discharge of a BCC granted under this
clause shall comply with the following:
(AA)
Not result in any less stringent limitations than those existing upon or after
the effective date of this rule.
(BB) Not likely jeopardize the continued
existence of any endangered or threatened species listed under Section 4 of the
ESA or result in the destruction or adverse modification of such species'
critical habitats.
(CC) Be limited
to one (1) permit term unless the commissioner makes a new determination in
accordance with this subdivision for each successive permit application in
which a mixing zone for the BCC is sought.
(DD) Reflect all information relevant to the
size of the mixing zone considered under item (ii).
(EE) Protect all designated and existing uses
of the receiving water.
(FF) Meet
all applicable aquatic life, wildlife, and human health criteria and values at
the edge of the mixing zone and, as appropriate, within the mixing zone or be
consistent with any appropriate TMDL or such other strategy consistent with
this section.
(GG) Ensure the
discharger has developed and conducted a pollutant minimization program for the
BCC if required to do so under section 11.6 of this rule.
(HH) Ensure that alternative means for
reducing BCCs elsewhere in the watershed are evaluated.
(G) For each draft NPDES permit
that would allow a mixing zone for one (1) or more BCCs after January 1, 2004,
the fact sheet or statement of basis for the draft permit, shall:
(i) specify the mixing provisions used in
calculating the permit limits; and
(ii) identify each BCC for which a mixing
zone is proposed.
(2) The following addresses conditions for
deriving TMDLs, WLAs in the absence of TMDLs, and preliminary WLAs for open
waters of Lake Michigan, inland lakes, and other waters of the Great Lakes
system with no appreciable flow relative to their volumes:
(A) For discharges into the open waters of
Lake Michigan, the following requirements apply:
(i) To prevent acute toxicity to aquatic
life, WLAs established in a TMDL, WLAs in the absence of a TMDL, and
preliminary WLAs shall be determined as follows:
(AA) For allocations based on an acute
aquatic life criterion or value, the CMC or SMC shall not be exceeded outside
the zone of initial dilution and the FAV shall not be exceeded in the undiluted
discharge, unless a mixing zone demonstration is conducted and approved under
subdivision (4), in which case the CMC or SMC shall be met outside the
applicable alternate mixing zone.
(BB) For allocations implementing the
narrative acute WET criterion, one and zero-tenths (1.0)
TUa shall not be exceeded in the undiluted discharge,
unless a mixing zone demonstration is conducted and approved under subdivision
(4), in which case three-tenths (0.3) TUa shall be met
outside the applicable alternate mixing zone.
(ii) To prevent chronic toxicity to aquatic
life, human health, and wildlife, WLAs established in a TMDL, WLAs in the
absence of a TMDL, and preliminary WLAs shall be determined as follows:
(AA) For allocations based on a chronic
criterion or value (CCC or SCC; HNC or HNV; HCC or HCV; or WC or WV), the
chronic criterion or value shall not be exceeded in the undiluted discharge
unless a mixing zone demonstration is conducted and approved under subdivision
(4), in which case the chronic criterion or value shall be met outside the
applicable alternate mixing zone.
(BB) For allocations implementing the
narrative chronic WET criterion, one and zero-tenths (1.0)
TUc shall not be exceeded in the undiluted discharge
unless a mixing zone demonstration is conducted and approved under subdivision
(4), in which case one and zero-tenths (1.0) TUc shall
be met outside the applicable alternate mixing zone.
(iii) WLAs established in a TMDL, WLAs in the
absence of a TMDL, and preliminary WLAs based on the criterion for chloride,
sulfate, total dissolved solids, fluoride, or dissolved iron under
327 IAC
2-1.5-8(j) shall ensure that the
criterion not be exceeded in the undiluted discharge unless a mixing zone
demonstration is conducted and approved under subdivision (4), in which case
the criterion shall be met outside the applicable alternate mixing
zone.
(iv) If mixing zones from two
(2) or more proximate sources interact or overlap, the combined effect must be
evaluated to ensure that applicable criteria and values will be met in the area
where any applicable mixing zones overlap.
(v) In no case shall a mixing zone be granted
that exceeds the area where discharge-induced mixing occurs.
(B) For discharges into inland
lakes and other waters of the Great Lakes system with no appreciable flow
relative to their volumes (other than the open waters of Lake Michigan), no
mixing zone will be allowed and water quality criteria or values will apply to
the undiluted discharge.
(C)
Appropriate mixing zone assumptions to be used in calculating load allocations
for nonpoint sources shall be determined on a case-by-case basis.
(D) In no case shall a mixing zone be granted
that would likely jeopardize the continued existence of any endangered or
threatened species listed under Section 4 of the ESA or result in the
destruction or adverse modification of such species' critical
habitats.
(3) The
following describes conditions for deriving TMDLs, WLAs in the absence of
TMDLs, and preliminary WLAs for tributaries of the Great Lakes system that
exhibit appreciable flows relative to their volumes:
(A) The following stream design flows shall
be used unless data exist to demonstrate that an alternative stream design flow
is appropriate for stream-specific and pollutant-specific conditions:
(i) For purposes of calculating a TMDL, WLAs
in the absence of a TMDL, or preliminary WLAs, using a steady-state model, the
stream design flows shall be as follows:
(AA)
For an acute aquatic life criterion or value, the one (1) day, ten (10) year
stream design flow (Q1,10).
(BB) To implement the narrative acute WET
criterion, when a mixing zone demonstration is conducted and approved under
subdivision (4), the one (1) day, ten (10) year stream design flow
(Q1,10).
(CC) For a chronic aquatic life criterion or
value, the seven (7) day, ten (10) year stream design flow
(Q7,10).
(DD) To implement the narrative chronic WET
criterion, the seven (7) day, ten (10) year stream design flow
(Q7,10).
(EE) For a drinking water human health
criterion or value, the harmonic mean flow at the point of the public water
system intake.
(FF) For a
nondrinking water human health criterion or value, the harmonic mean flow at
the point of discharge.
(GG) For a
WC or WV, the ninety (90) day, ten (10) year stream design flow
(Q90,10).
(ii) TMDLs, WLAs in the absence of TMDLs, and
preliminary WLAs calculated using dynamic modelling do not need to incorporate
the stream design flows specified in item (i).
(iii) TMDLs, WLAs in the absence of TMDLs,
and preliminary WLAs calculated for intermittent or controlled discharges may
use alternate stream design flows if these alternate design flows will ensure
compliance with water quality criteria and values.
(B) To prevent acute toxicity, WLAs and LAs
established in a TMDL, WLAs in the absence of a TMDL, and preliminary WLAs
shall be determined as follows:
(i) For
allocations based on an acute aquatic life criterion or value, the CMC or SMC
shall not be exceeded outside the zone of initial dilution and the FAV shall
not be exceeded in the undiluted discharge unless a mixing zone demonstration
is conducted and approved under subdivision (4), in which case the CMC or SMC
shall be met outside the applicable alternate mixing zone.
(ii) For allocations implementing the
narrative acute WET criterion, one and zero-tenths (1.0)
TUa shall not be exceeded in the undiluted discharge
unless a mixing zone demonstration is conducted and approved under subdivision
(4), in which case three-tenths (0.3) TUa shall be met
outside the applicable alternate mixing zone.
(C) To protect aquatic life, wildlife, and
human health from chronic effects, including chronic WET, WLAs and LAs
established in a TMDL, WLAs in the absence of a TMDL, and preliminary WLAs
shall be calculated using a dilution fraction no greater than twenty-five
percent (25%) of the stream design flow unless a mixing zone demonstration
under subdivision (4) is conducted and approved.
(D) If mixing zones from two (2) or more
proximate sources interact or overlap, the combined effect must be evaluated to
ensure that applicable criteria and values will be met in the area where any
applicable mixing zones overlap.
(E) In no case shall a permitting authority
grant a mixing zone that would likely jeopardize the continued existence of any
endangered or threatened species listed under Section 4 of the ESA or result in
the destruction or adverse modification of such species' critical
habitats.
(4) An
alternate mixing zone that is allowed under subdivision (2) or (3) may be
granted upon the request of the discharger subject to the following
requirements:
(A) Alternate mixing zones are
granted on a pollutant-by-pollutant and criterion-by-criterion basis. Any
discharger seeking a mixing zone other than that specified by subdivision (2)
or (3) shall submit an application for an alternate mixing zone for
consideration by the commissioner. The alternate mixing zone application must
do the following:
(i) Document the
characteristics and location of the outfall structure, including whether
technologically-enhanced mixing will be utilized.
(ii) Document the amount of dilution
occurring at the boundaries of the proposed mixing zone and the size, shape,
and location of the area of mixing, including the manner in which diffusion and
dispersion occur.
(iii) For sources
discharging to the open waters of Lake Michigan, define the location at which
discharge-induced mixing ceases.
(iv) For sources discharging to tributaries
of the Great Lakes system that exhibit appreciable flows relative to their
volumes and seeking an alternate mixing zone for an acute aquatic life
criterion or value or for acute WET, define the location at which
discharge-induced mixing ceases under stream design flow conditions.
(v) Document the physical, including
substrate character and geomorphology, chemical, and biological characteristics
of the receiving waterbody, including whether the receiving waterbody supports
indigenous, endemic, or naturally occurring species.
(vi) Document the physical, chemical, and
biological characteristics of the effluent.
(vii) Document the synergistic effects of
overlapping mixing zones or the aggregate effects of adjacent mixing
zones.
(viii) Show whether
organisms would be attracted to the area of mixing as a result of the effluent
character.
(B) The
commissioner may grant the alternate mixing zone if the discharger demonstrates
the following:
(i) The mixing zone would not
interfere with or block passage of fish or aquatic life.
(ii) The level of the pollutant permitted in
the waterbody would not likely jeopardize the continued existence of any
endangered or threatened species listed under Section 4 of the ESA or result in
the destruction or adverse modification of such species' critical
habitats.
(iii) The mixing zone
would not extend to drinking water intakes.
(iv) The mixing zone would not impair or
otherwise interfere with the designated or existing uses of the receiving water
or downstream waters.
(v) The
mixing zone would not promote undesirable aquatic life or result in a dominance
of nuisance species.
(vi) By
allowing the additional mixing:
(AA)
substances will not settle to form objectionable deposits;
(BB) floating debris, oil, scum, and other
matter in concentrations that form nuisances will not be produced;
and
(CC) objectionable color, odor,
taste, or turbidity will not be produced.
(C) In no case shall an alternate mixing zone
for an acute aquatic life criterion or value or for acute WET be granted unless
the discharger utilizes a submerged, high rate diffuser outfall structure (or
the functional equivalent) that provides turbulent initial mixing and minimizes
organism exposure time.
(D) In no
case shall an alternate mixing zone for an acute aquatic life criterion or
value or for acute WET be granted that exceeds the area where discharge-induced
mixing occurs.
(E) In no case shall
an alternate mixing zone for a discharge into the open waters of Lake Michigan
be granted that exceeds the area where discharge-induced mixing
occurs.
(F) Upon receipt of an
application for an alternate mixing zone, the commissioner shall provide
notice, request comment, and, if requested, schedule and hold a public meeting
on the application in accordance with section 11.2 of this
rule.
(5) Except for
discharges into the open waters of Lake Michigan, notwithstanding subdivisions
(2) through (4), the commissioner may deny any mixing zone for:
(A) a discharge;
(B) certain substances in a discharge;
or
(C) a criterion or value for any
substance in a discharge;
based upon a determination of adverse human health, aquatic life, or wildlife effects. The commissioner shall identify and document the rationale for this decision.
(6) For discharges into the open waters of
Lake Michigan, if all of the conditions for approval of an alternate mixing
zone are met in accordance with subdivision (4), the alternate mixing zone
shall be granted unless the commissioner determines that the mixing zone should
be denied based upon a consideration of harm to human health, aquatic life, or
wildlife. The commissioner shall evaluate all available information, including
information submitted by the public, relevant to the consideration of harm to
human health, aquatic life, or wildlife. The commissioner shall identify the
harm to human health, aquatic life, or wildlife, and document the rationale for
this decision.
(7) The
commissioner's evaluation of a mixing zone for a discharge into the open waters
of Lake Michigan under subdivisions (2), (4), and (6) shall constitute the
evaluation required by IC 13-18-4-7. Any decision regarding the granting or
denial of a mixing zone for a discharge into Lake Michigan shall be included in
the public notice of the tentative decision on the draft new, renewed, or
modified permit. The basis for the tentative decision, including the
commissioner's rationale for concluding whether or not the requirements of IC
13-18-4-7 are satisfied, shall be included in the briefing memo or fact sheet
that accompany the tentative decision on the draft new, renewed, or modified
permit.
(c) WLAs calculated in the absence of a TMDL and preliminary WLAs shall be determined using the conservation of mass equations as follows unless an alternate methodology is approved by the commissioner:
(1) For the calculations contained within
this subsection, the following apply:
| (A) | WQCc | = | The chronic water quality criterion or value. A chronic water quality criterion or value is any of the following: |
| (i) CCC or SCC. If the CCC or SCC for a metal is expressed in the form of dissolved metal, the CCC or SCC shall be set equal to Cinstream determined for the CCC or SCC in accordance with subdivision (6). | |||
| (ii) The numeric interpretation of the narrative chronic WET criterion (one and zero-tenths (1.0) TUc). | |||
| (iii) HNC or HNV. | |||
| (iv) HCC or HCV. | |||
| (v) WC or WV. | |||
| (vi) The criterion for chloride, sulfate, total dissolved solids, fluoride, or dissolved iron under 327 IAC 2-1.5-8(j). | |||
| (B) | WQCa | = | The CMC or SMC or, if a mixing zone demonstration for acute WET is conducted and approved under subsection (b)(4), three-tenths (0.3) TUa for WET. If the CMC or SMC for a metal is expressed in the form of dissolved metal, the CMC or SMC shall be set equal to Cinstream determined for the CMC or SMC in accordance with subdivision (8). |
| (C) | FAV | = | Two (2) times the CMC or SMC. If the CMC or SMC for a metal is expressed in the form of dissolved metal, the FAV shall equal two (2) times Cinstream determined for the CMC or SMC in accordance with subdivision (8). |
| (D) | Qe | = | The facility effluent flow as determined by subsection (a)(9). |
| (E) | Qw | = | The portion of the receiving waterbody allocated for mixing under subsection (b). If Cb is greater than the water quality criterion or value, a value of zero (0) shall be used for Qw. |
| (F) | Cb | = | The representative background concentration determined by subsection (a)(8). |
| (G) | DF | = | Dilution factor = Click to view image |
| (H) | Qz | = | The portion of the receiving waterbody allocated for mixing in the zone of initial dilution. For discharges into tributaries that exhibit appreciable flows relative to their volumes, Qz = Qe or the Q1,10, whichever is less. For discharges into the open waters of Lake Michigan, Qz = Qe. If Cb is greater than WQCa, a value of zero (0) shall be used for Qz. |
(2)
WLAs for discharges into tributaries that exhibit appreciable flows relative to
their volumes based on protection from acute aquatic effects shall be
determined as follows:
(A) For a discharge
without an approved alternate mixing zone under subsection (b)(4), the equation
resulting in the lesser WLA shall be used:
(i) WLA = FAV (or 1.0
TUa for WET); or
(ii)
Click to
view image
(B) For a discharge with an approved
alternate mixing zone under subsection (b)(4), the following equation shall be
used:
(3) WLAs for discharges into tributaries that
exhibit appreciable flows relative to their volumes based on protection from
chronic effects shall be determined as follows:
(4) WLAs
for discharges into the open waters of Lake Michigan based on protection from
acute aquatic effects shall be determined as follows:
(A) For a discharge without an approved
alternate mixing zone under subsection (b)(4), the equation resulting in the
lesser WLA shall be used:
(i) WLA = FAV (or
1.0 TUa for WET); or
(ii)
Click to
view image
(B) For a discharge with an approved
alternate mixing zone under subsection (b)(4), the following equation shall be
used:
(5) WLAs for discharges into the open waters
of Lake Michigan based on protection from chronic effects shall be determined
as follows:
(A) For a discharge without an
approved alternate mixing zone under subsection (b)(4), the following equation
shall be used:
WLA = WQCc
(B) For a discharge with an approved
alternate mixing zone under subsection (b)(4), the following equation shall be
used:
WLA = (WQCc)(DF) - (Cb)(DF-1)
(6) WLAs for discharges into inland lakes and
other waters of the Great Lakes system with no appreciable flow relative to
their volumes (other than the open waters of Lake Michigan) based on protection
from acute aquatic effects shall be determined as follows:
WLA = WQCa
(7) WLAs for discharges into inland lakes and
other waters of the Great Lakes system with no appreciable flow relative to
their volumes (other than the open waters of Lake Michigan) based on protection
from chronic effects shall be determined as follows:
WLA = WQCc
(8) The following procedures shall be used to
calculate Cinstream, the total recoverable metal
concentration outside the mixing zone that equates to an acute or chronic
aquatic life water quality criterion or value expressed in the form of
dissolved metal:
(A) For a CMC or SMC
expressed in the form of dissolved metal, Cinstream
shall be calculated by dividing the CMC or SMC by the acute translator found in
clause (D).
(B) For a CCC or SCC
expressed in the form of dissolved metal, Cinstream
shall be calculated by dividing the CCC or SCC by the chronic translator found
in clause (D).
(C) If all approved
analytical methods for the metal inherently measure only its dissolved form,
such as hexavalent chromium, Cinstream shall not be
calculated and the acute and chronic aquatic life water quality criteria or
values expressed in the form of dissolved metal shall be used in the
calculation of WLAs.
(D) Unless a
site-specific translator is determined in accordance with clause (E), the
following translators shall be used:
| Table 11.4-2 | ||
| Metals Translators | ||
| Dissolved to Total Recoverable | ||
| Acute | Chronic | |
| Substances | Translators | Translators |
| Arsenic (III) | 1.000 | 1.000 |
| Cadmium | 1.136672-[(ln hardness)(0.041838)] | 1.101672-[(ln hardness)(0.041838)] |
| Chromium (III) | 0.316 | 0.860 |
| Copper | 0.960 | 0.960 |
| Mercury | 0.85 | 0.85 |
| Nickel | 0.998 | 0.997 |
| Selenium | 0.922 | 0.922 |
| Zinc | 0.978 | 0.986 |
(E)
A discharger or proposed discharger may request the use of an alternate
translator by using site-specific data. The discharger must conduct a
site-specific study to identify the ratio of the dissolved fraction to the
total recoverable fraction for a metal in the receiving waterbody outside the
mixing zone. If the discharger provides an acceptable study, and other
provisions of 327 IAC 2-1.5 and this article are satisfied (such as
antibacksliding and antidegradation), the commissioner shall use the
site-specific translator. A translator derived for one (1) discharge into a
waterbody segment may be applied to other discharges on the same waterbody
segment if the translator would adequately represent the site-specific
conditions applicable to the other discharges.
(d) Notwithstanding subsections (a) through (c), the pollutants contained in this subsection shall be addressed as follows:
(1) The pH requirements contained in
327 IAC
2-1.5-8(c)(2) and
327 IAC
2-1.5-8(j) apply to the undiluted
discharge.
(2) The bacteriological
criteria contained in
327 IAC
2-1.5-8(e) apply to the undiluted
discharge.
(3) Models, approved by
the commissioner, that ensure compliance with the applicable water quality
criteria for the following parameters shall be used:
(A) Dissolved oxygen criteria contained in
327 IAC
2-1.5-8(c)(3),
327 IAC
2-1.5-8(d)(1), and
327 IAC
2-1.5-8(j).
(B) Thermal requirements contained in
327 IAC
2-1.5-8(c)(4) and
327 IAC
2-1.5-8(d)(2).
(C) Criteria for the protection of public
water supplies contained under
327 IAC
2-1.5-8(f).
(D) Criteria for the protection of industrial
water supplies contained in
327 IAC
2-1.5-8(g).
Disclaimer: These regulations may not be the most recent version. Indiana may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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