Notice of Intent To Prepare an Environmental Impact Statement for the Scoggins Dam Safety Modifications Project, 4989-4991 [2024-01410]

Agencies

• DEPARTMENT OF THE INTERIOR
• Bureau of Reclamation

[Federal Register Volume 89, Number 17 (Thursday, January 25, 2024)]
[Notices]
[Pages 4989-4991]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-01410]


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DEPARTMENT OF THE INTERIOR

Bureau of Reclamation

[RR01021200; 23XR0680A5; RX.15470004.00118T0]


Notice of Intent To Prepare an Environmental Impact Statement for 
the Scoggins Dam Safety Modifications Project

AGENCY: Bureau of Reclamation, Interior.

ACTION: Notice of intent; request for comments.

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SUMMARY: The Bureau of Reclamation (Reclamation) intends to prepare an 
environmental impact statement (EIS) for the Scoggins Dam Safety 
Modifications Project in the Tualatin Basin, Oregon. The purpose of the 
project is to improve public safety by reducing risk associated with 
severe seismic loadings while continuing to meet authorized project 
purposes. Reclamation is seeking public comments to identify 
significant issues or other alternatives to be addressed in the EIS.

DATES: Submit written comments on the scope of the EIS on or before 
February 26, 2024.
    Reclamation will hold two in-person and two web-based virtual 
public scoping meetings on the following dates:
    1. February 8, 2024, 5 p.m. to 6:30 p.m. (PST), Forest Grove, OR.
    2. February 8, 2024, 6:30 p.m. to 8 p.m. (PST), Forest Grove, OR.
    3. February 13, 2024, 11 a.m. to 1 p.m. (PST), Virtual (Zoom 
webinar).
    4. February 13, 2024, 4 p.m. to 6 p.m. (PST), Virtual (Zoom 
webinar).

ADDRESSES: Send written scoping comments, requests to be added to the 
project mailing list, or requests for other special assistance needs 
via email to [email protected].
    The in-person meetings will be held at the Community Auditorium, 
1915 Main Street, Forest Grove, OR 97116.
    The web-based virtual meetings will be accessible at: https://www.virtualpublicmeeting.com/scoggins-sod-eis.
    To view more information regarding this project, go to: https://www.usbr.gov/pn/programs/sod/scoggins/.

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FOR FURTHER INFORMATION CONTACT: Rebecca Thompson, Bureau of 
Reclamation, Columbia-Pacific Northwest Regional Office, 1150 Curtis 
Road, Suite 100, Boise, Idaho 83706-1234; telephone (208) 600-2134; 
email [email protected].
    Individuals who are deaf, deafblind, hard of hearing, or have a 
speech disability may dial 711 (TTY, TDD, or TeleBraille) to access 
telecommunications relay services to contact the above individual 
during normal business hours or to leave a message or question after 
hours. You will receive a reply during normal business hours.

SUPPLEMENTARY INFORMATION: This Federal Register notice provides the 
public with information regarding Reclamation's intent to prepare an 
EIS pursuant to the National Environmental Policy Act (NEPA) of 1969, 
as amended. Reclamation will hold public scoping meetings to solicit 
comments on the scope of the EIS and the issues and alternatives that 
should be analyzed. Additionally, this notice serves to provide notice 
and request public input on potential effects on historic properties 
from this project in accordance with the Section 106 process as defined 
in the National Historic Preservation Act (36 CFR 800.2(d)(3)).

Background

    Scoggins Dam is an earthfill embankment dam located on Scoggins 
Creek, a tributary of the Tualatin River, about 25 miles west of 
Portland, Oregon. Construction of this 151-foot-high, 2,700-foot-long 
dam was completed in 1975. The dam's reservoir, Henry Hagg Lake, is the 
primary source of water for the Tualatin Basin, storing nearly 60,000 
acre-feet (active 53,600 acre-feet), providing water for municipal and 
industrial uses, irrigation, water quality, fish and wildlife habitat, 
recreation, and flood control. The facility is operated and maintained 
by the Tualatin Valley Irrigation District. There are roughly 11 miles 
of shoreline around the lake at full pool; recreation facilities and 
trails in this area are managed by Washington County as Scoggins Valley 
Park.
    The area of Scoggins Dam and its reservoir have high potential for 
severe loading initiated by an extreme seismic event from identified 
active faults, primarily the Cascadia Subduction Zone (CSZ), a 600-mile 
fault stretching from northern California to northern Vancouver Island 
in Canada. At its closest, the CSZ is 118 miles to the west of the dam. 
The principal concerns for Scoggins Dam are uncontrolled releases or 
dam breaches (dam failure) caused by severe loading from a CSZ seismic 
event. The dam could also experience less severe loading from local 
crustal fault earthquakes, the closest being the Gales Creek fault 
zone.
    Around 2007, after completing general investigations of potential 
seismic hazards at the dam, Reclamation recognized the potential 
impacts of a CSZ seismic event to Scoggins Dam. Reclamation continued 
field data collection and evaluation and risk analyses updates through 
2011 to improve the understanding of seismic risk to the dam. Since 
2011, Reclamation has looked at various structural and non-structural 
options to reduce seismic risk, including options that would increase 
reservoir storage. In 2022, following completion of a Dam Safety 
Advisory Team review, Reclamation began furthering design of a dam-
safety only structural option that would reduce risk in accordance with 
Reclamation's public protection guidelines. This alternative will be 
evaluated in the EIS.

Proposed Action

    Reclamation proposes to reduce the risk to Scoggins Dam in the 
occurrence of a CSZ seismic event by improving the loadings response 
performance of the facility. This would be accomplished by raising the 
dam crest, constructing a downstream shear key, creating a new 
spillway, and placing additional berm material over the existing dam. 
This project would not create additional reservoir storage in Henry 
Hagg Lake.
    Proposed dam structure modifications include:
     Excavate and backfill portions of the crest and existing 
embankment.
     Construct a downstream shear key.
     Install a downstream rock filter and drain.
     Install a stability berm over the shear key and downstream 
slope of dam.
     Raise the dam crest by ~7 feet.
     Demolish the existing spillway, bridge, and ancillary 
features.
     Construct a new spillway, bridge, and ancillary features 
and extend outlet works.
     Construct a new two-lane road across the dam.
    The existing road across the dam would be closed during 
construction. An alternative road would be constructed to provide safe 
public transport. The project may also require permanently rerouting a 
portion of the Stimson Mainline Road to accommodate the expanded 
stability berm.
    In addition to work on the dam, the project would include 
modification to structures around the reservoir such as culverts and 
recreation trails. Materials for construction would be excavated at one 
or more borrow sites on the east side of the reservoir, requiring the 
removal of large trees. Alternatives for accessing and transporting 
materials from the borrow sites will be investigated in the EIS and may 
include a combination of constructing a temporary haul route and using 
the existing Scoggins Valley Road.

Previous Water Supply Studies

    In 2001, the Tualatin Basin Water Supply Feasibility Study was 
initiated to evaluate a range of water supply options in the basin, 
including raising Scoggins Dam (publication in the Federal Register on 
December 13, 2001, 66 FR 64454). A draft EIS was prepared in 2007, but 
never published, due to the need to further evaluate the seismic risk 
of the CSZ to the dam. During 2013, some of the partners in the 
feasibility study began separately pursuing other water supply options 
that did not include Scoggins Dam or Reclamation participation. In 
2017, following receipt of a Joint Project Authority secured in 
amendments to the Safety of Dams Act in 2015, Reclamation began working 
jointly with Clean Water Services, analyzing the feasibility of three 
options (dam safety only modification, dam raise, and new downstream 
dam); all options would have reduced seismic risk at the dam, and two 
would have increased water supply in the basin. In 2021, a 
determination was made to forego further development of increasing 
reservoir storage and to support development of a dam safety only 
modification.

Statutory Authority and Anticipated Permits

    NEPA [42 U.S.C. 4321 et seq.] requires Federal agencies to conduct 
an environmental analysis of their proposed actions to determine 
whether the actions may significantly affect the human environment. The 
EIS will analyze the environmental effects of implementing the proposed 
action and alternatives, and a no action alternative. The U.S. Army 
Corps of Engineers, Tualatin Valley Irrigation District, Washington 
County, Joint Water Commission, Clean Water Services, and Confederated 
Tribes of the Grand Ronde Community of Oregon have accepted invitations 
to participate as cooperating agencies for the EIS. Other entities will 
be considered, as necessary, during the EIS process. In addition to 
NEPA, various other Federal, state, and local authorizations may be 
required for the proposed action. Applicable Federal laws include, but 
are not limited to, the Endangered Species Act, National

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Historic Preservation Act, and Clean Water Act.

Public Disclosure

    Before including your address, phone number, email address, or 
other personal, identifying information in your comment submission, 
please be advised that the entire submission, including your personal 
identifying information, may be made publicly available at any time. 
While a commenter may request that Reclamation withhold personal 
identifying information from public review, Reclamation cannot 
guarantee that it will be able to do so.

How To Request Reasonable Accommodation

    For special assistance at one of the scoping meetings, please 
contact Rebecca Thompson or the TDD line (see FOR FURTHER INFORMATION 
CONTACT section of this notice) at least 5 working days before the 
meetings. All meeting facilities are physically accessible to people 
with disabilities. Information regarding this project is available in 
alternate formats upon request.

Jennifer Carrington,
Regional Director, Columbia-Pacific Northwest Region, Bureau of 
Reclamation.
[FR Doc. 2024-01410 Filed 1-24-24; 8:45 am]
BILLING CODE 4332-90-P