Permit Application Public Notices

The United States Congress authorizes the U.S. Army Corps of Engineers to regulate activities that may impact wetlands and waters of the United States. This authority is granted and defined under Section 10 of the Rivers and Harbors Act of 1899 and Section 404 of the Federal Water Pollution Control Act Amendments of 1972, also known as the Clean Water Act.

Public involvement is a key element of the Corps’ permit review process. During an application review, the Corps considers the views of other federal, state and local agencies, Native American tribes, interest groups, and the general public. The results of this careful public interest review are fair and equitable decisions that allow reasonable use of private property, infrastructure development, and growth of the economy, while offsetting the authorized impacts to the waters of the United States.

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Portland District
Published Sept. 20, 2023
Expiration date: 10/19/2023

Application for Permit

Issue Date: September 19, 2023
Expiration Date: October 19, 2023
30-Day Notice
U.S. Army Corps of Engineers No: NWP-2023-248

Interested parties are hereby notified the U.S. Army Corps of Engineers, Portland District (Corps) has received an application for a Department of the Army permit for certain work in waters of the United States, as described below and shown on the attached drawings. The Corps is soliciting comments on the proposed work.

Applicant: Idaho Power Company
Attention: Justin Hitt
1221 W. Idaho Street 
Boise, ID 83702
Telephone: (208) 949-4220

Applicant’s Agent:Tetra Tech, Inc. 
Attention: Walt Vering
3380 Americana Terrace, Suite 201
Boise, ID 83706
Telephone: (208) 489-2828

Location: The project site is located at 48001 Power Plant Lane, in Oxbow, Baker County, Oregon. The site is in Section 10, Township 07 South, Range 48 East. Latitude and Longitude: 44.9717° North, 116.8366° West.

Waterway: The proposed actions would occur in the Snake River Hells Canyon Reservoir at approximately river mile 273. The location of the ordinary high water mark (OHWM) shown on the project drawings have not yet been verified by the Corps. If the Corps determines the boundaries of the wetland/waters are substantially inaccurate a new public notice may be published.

Project Purpose: The applicant’s stated purpose is to repair the downstream end of the Oxbow Dam spillway.

Project Description: The proposed project is the Oxbow Dam Spillway Repair Project. The Oxbow Hydroelectric Project includes a zoned rockfill embankment dam with a service spillway on the Oregon abutment and an emergency fuse plug spillway on the Idaho abutment. The current spillway design creates erosive forces downstream of the spillway and a large scour hole has developed immediately below the existing structure.
The proposed project would occur in the area from the base of the spillway to approximately a few hundred feet downstream. Construction would be confined within a nine-month timeframe, from May 1, 2024 to February 1, 2025.

The proposed project would include the following elements specific to the Corps’ role in evaluating the repair project:

In-water work area isolation and dewatering:

The applicant would install a temporary 30-inch high-density polyethylene pipeline and isolation valve to divert the minimum required spillway flow around the proposed work area where the repairs would occur. The diversion flow would discharge on the Idaho side of the Snake River. To facilitate construction of spillway repairs in the dry, the applicant would temporarily discharge up to 8,150 cubic yards (cy) of imported clean gravel and rock waterward of the OHWM within an approximate 0.43-acre area on the Idaho side of the Snake River to construct cofferdam number one. A large crane equipped with clamshell bucket and staged in uplands would be used to construct the cofferdam. Once cofferdam number one is constructed, fish salvage would commence within the isolated work area and would continue as screened pumps dewater the isolated work area.

Cofferdam number two would be constructed only if determined necessary to prevent backflow into the proposed project area. The applicant would temporarily discharge up to 450 cy of imported clean gravel and rock waterward of the OHWM within an approximate 0.13-acre area on the Oregon side of the Snake River to construct cofferdam number two.

Service spillway demolition and repair:

The proposed repair design includes the following spillway remediation measures:

• Removing and replacing of a portion of the existing downstream sloped concrete spillway slab including installation of a grid of rock dowels to resist uplift forces;
• Repairing additional voids beneath the spillway discovered during removal of the existing concrete slab;
• Constructing a toe trench into sound rock below the existing scour elevation; and
• Filling the downstream scour hole with native boulders, cobbles, and gravels grouted in-place.

The applicant would discharge up to 10,465 cy of grouted native boulders, cobbles, and gravels waterward of the OHWM within an approximate 0.51-acre area downstream of the spillway up to the to the top of the spillway toe to fill the scour hole and help mitigate further scouring. The applicant would discharge up to 15,500 cy of concrete within an approximate 0.52-acre area waterward of the OHWM to repair a portion of the sloped concrete spillway slab without expanding on the existing structure.

Excavation of onsite native streambed material for scour hole fill:

Fill materials proposed as fill for the scour hole would be excavated from an instream area of sediment deposition, denoted as the river rock/quarry area on the attached project drawings, located waterward of the Snake River OHWM. Sediments in this area are primarily sediments that have eroded from the scour hole location and consist of boulders, cobbles, and gravels with limited fine sediments. The applicant would conduct mechanical dredging (excavation) of the following amounts of streambed sediments from the river rock/quarry area:

• Up to 8,200 cy from an approximate 1.10-acre area below the OHWM on the Oregon side of the Snake River;
• Up to 3,750 cy from an approximate 0.95-acre area above the OHWM on the Oregon side of the Snake River; and
• Up to 12,400 cy from an approximate 1.03-acre area above the OHWM on the Idaho side of the Snake River

The applicant would screen the excavated streambed sediments prior to discharge into the scour fill area. Any sediments which do not meet the engineering specifications for the scour hole fill material would be hauled by dump truck to a temporary stockpiling area located in uplands and eventually removed offsite.

Dredged Material Testing: The proposed dredged material will be evaluated in accordance with the Sediment Evaluation Framework for the Pacific Northwest (SEF). The interagency Portland Sediment Evaluation Team (PSET) implements the SEF for the Corps Portland District. The PSET will determine if sediment testing is required for this project. Project sediments may require physical, chemical, and/or biological testing to support the permit application evaluation. The PSET will evaluate the applicant’s sediment testing results and determine if project sediments are suitable for unconfined, aquatic disposal and exposure. 

Mitigation: The applicant proposes to avoid and minimize impacts from the project primarily by isolating the proposed construction activities from river flows and limiting the amount of fill to that only necessary to make the repair of the currently serviceable structure. The applicant would implement erosion and sediment control and in-water work best management practices (BMPs) to further avoid and minimize impacts. BMPs would include but not be limited to:

• Utilizing erosion and sediment control BMPs such as silt fence, straw matting or bales);
• Designating staging, stockpile, and storage areas, and/or containment for equipment and hazardous materials;
• Designating concrete truck washout areas and offsite removal of remaining cured washout concrete;
• Returning access paths, staging, stockpile, and storage areas to original grades and lines post-construction;
• Installing impermeable polyethylene sheet liner, six-millimeter thickness, on downstream faces of temporary cofferdams to serve as a water barrier;
• Prior to release into the river, pumping sediment-laden water to designated, contained treatment areas until discharge water would meet Clean Water Act Section 401 water quality standards for turbidity, as determined by the Oregon Department of Environmental Quality and the Idaho Department of Environmental Quality;
• Requiring observation and oversight from qualified fisheries biologist during placement and removal of cofferdams;
• Requiring dewatering pumps used during the initial dewatering period would utilize fish screens meeting the National Marine Fisheries Service (NMFS) fish screening criteria for anadromous salmonids; and
• Conducting fish salvage operations under the supervision of a qualified fisheries biologist and according to NMFS guidelines to remove all fish species from the isolated work area and releasing fish downstream of the project area.

The applicant did not propose compensatory mitigation in the permit application. The Corps will determine the type and amount of compensatory mitigation necessary to offset environmental losses from the proposed project.

Drawings: Twenty (20) drawings are attached and labeled Corps No. NWP-2023-248. Copies of this public notice, which have been mailed or otherwise physically distributed, feature project drawings in black and white. The electronic version features the drawings in color, which we think more accurately illustrates the proposed project. To access the electronic version of this public notice, go to the Portland District Regulatory website at and under Regulatory Pages select Permit Application Public Notices.

Additional Information: The Oxbow Hydroelectric Project is a 220-megawatt hydroelectric facility licensed as part of the Hells Canyon Complex, Federal Energy Regulatory Commission (FERC) Project No. 1971, and is owned and operated by Idaho Power Company. 

Authority: The proposed project will be evaluated under the following:
Section 10, Rivers and Harbors Act 1899 (33 U.S.C. 403), for work in or affecting navigable waters of the United States.
Section 404, Clean Water Act (33 U.S.C. 1344), for discharge of dredged or fill material into waters of the United States.

Clean Water Act Section 404(b)(1) Guidelines: The described discharge will be evaluated for compliance with guidelines promulgated by the U.S. Environmental Protection Agency under authority of Section 404(b)(1) of the Clean Water Act. The 404(b)(1) Guidelines are the substantive criteria used in evaluating discharges of dredged or fill material into waters of the United States. The source of the fill material for the scour hole would be the onsite river rock quarry area which is an instream deposition of streambed sediments immediately adjacent to the existing scour hole. The streambed sediments are primarily coarse native river sediments (cobbles and gravels). The source of the fill material for the cofferdams would be a local or regional rock quarry capable of supplying the required crushed and washed clean rock and angular rock fill.

Water Quality Certification: Section 401 of the Clean Water Act (33 U.S.C. 1341) requires applicants to obtain a water quality certification for proposed discharges into waters of the United States. A permit for the described work will not be issued until certification has been issued or is waived from the certifying states of Oregon and Idaho. Oregon’s notice for a water quality certification is attached.

Endangered Species: Section 7 of the Endangered Species Act (ESA) (16 U.S.C 1536) requires federal agencies to consult with the National Marine Fisheries Service (NMFS) and/or U.S. Fish and Wildlife Service (USFWS) on all actions that may affect a species listed (or proposed for listing) under the ESA as threatened or endangered or that may adversely modify designated critical habitat. The Corps’ preliminary review indicates the described activity may affect bull trout or bull trout designated critical habitat. For this project, the FERC, as the lead Federal agency for ESA consultation completed consultation with the USFWS as required under Section 7 of the ESA. The USFWS issued a biological opinion for this project on May 1, 2023 and concluded that the action will not jeopardize the continued existence of bull trout.

Historic Properties/Cultural Resources: Section 106 of the National Historic Preservation Act (NHPA) of 1966, as amended (16 U.S.C. 470), requires Federal agencies to consult with the appropriate State and/or Tribal Historic Preservation Officer to take into account the effects of actions they undertake or permit on historic properties listed in or eligible for listing in the National Register of Historic Places. For this project, the FERC, as the lead Federal agency for determining compliance with Section 106 of the NHPA, has consulted for Section 106 with the appropriate State and/or Tribal Historic Preservation Officers as applicable. 

State and Local Authorizations: The applicant has applied for the following additional governmental authorizations for the project: removal-fill permit from the Oregon Department of State Lands (DSL) (DSL No. 64489-NP), water quality certification from the Oregon Department of Environmental Quality, and a floodplain development permit from Baker County, Oregon Planning Department. The applicant will apply for an Idaho Department of Environmental Quality review under Clean Water Act Section 401.

Public Hearing: Any person may request in writing within the comment period specified in this notice that a public hearing be held to consider this application. Requests for public hearings shall state with particularity the reasons for holding a public hearing.

Evaluation: The decision whether to issue a permit will be based on an evaluation of the probable impact, including cumulative impacts, of the described activity on the public interest. That decision will reflect the national concern for both protection and utilization of important resources. The benefit, which reasonably may be expected to accrue from the described activity, must be balanced against its reasonably foreseeable detriments. All factors, which may be relevant to the proposal will be considered including the cumulative effects thereof; among those are conservation, economics, aesthetics, general environmental concerns, wetlands, historic properties, fish and wildlife values, flood hazards, floodplain values, land use, navigation, shoreline erosion and accretion, recreation, water supply and conservation, water quality, energy needs, safety, food and fiber production, mineral needs, consideration of property ownership and, in general, the needs and welfare of the people.

The Corps is soliciting comments from the public; Federal, state, and local agencies and officials; Native American Tribes; and other interested parties in order to consider and evaluate the impacts of the proposed activity. Any comments received will be considered by the Corps to determine whether to issue, modify, condition or deny a permit for this proposal. To make this decision, comments are used to assess impacts on endangered species, historic properties, water quality, general environmental effects, and the other public interest factors listed above. Comments are used in the preparation of an Environmental Assessment and/or an Environmental Impact Statement pursuant to the National Environmental Policy Act. Comments are also used to determine the need for a public hearing and to determine the overall public interest of the proposed activity.

Submitting Comments: Interested parties are invited to provide comments on the proposed project. Comments may be submitted by conventional mail or email. All comments received will be considered in determining whether authorizing the work would be contrary to the public interest. 

Either conventional mail or e-mail comments must include the Corps reference number as shown on page 1 and include the commenter’s name and address. In order to be accepted, e-mail comments must originate from the author’s e-mail account and must include on the subject line of the e-mail message the Corps reference number. All comments received will become part of the administrative record and are subject to public release under the Freedom of Information Act including any personally identifiable information such as names, phone numbers, and addresses.

Additional information about the proposed project may be obtained from the Corps Project Manager listed below. All comments, whether by conventional mail or email, must be received no later than the expiration date of this public notice to ensure consideration. Comments should be submitted to the following mailing address or email address:

U.S. Army Corps of Engineers
Regulatory Branch
Mr. Michael Neal 
P.O. Box 2946
Portland, Oregon 97208-2946
Telephone: (503) 808-4380


Oregon Department of Environmental Quality (DEQ)
Water Quality 401 Certification

Notice Issued: September 19, 2023
Written Comments Due: October 19, 2023

Corps of Engineers No: NWP-2023-248
Oregon Department of State Lands No: APP 64489 

WHO IS THE APPLICANT: Idaho Power Company

LOCATION OF CERTIFICATION ACTIVITY: See attached U.S. Army Corps of Engineers public notice.

WHAT IS PROPOSED: See attached U.S. Army Corps of Engineers public notice on the proposed project.

NEED FOR CERTIFICATION: Section 401 of the Federal Clean Water Act requires applicants for Federal permits or licenses to provide the Federal agency a water quality certification from the State of Oregon if the proposed activity may result in a discharge to waters of the state.

DESCRIPTION OF DISCHARGES: See attached U.S. Army Corps of Engineers public notice on the proposed project.

WHERE TO FIND DOCUMENTS: Documents and materials related to water quality issues as a result of the proposal are available for examination and copying at Oregon Department of Environmental Quality, 401 Water Quality Permit Coordinator, Northwest Region, 700 NE Multnomah Street, Suite 600, Portland, Oregon 97232. Other project materials are available by contacting the Corps per the attached public notice.

Scheduling an appointment will ensure that water quality documents are readily accessible during your visit. To schedule an appointment please call DEQ Water Quality at Northwest Region at (503) 229-5623.

Any questions on the water quality certification process may be addressed to the 401 Permit Coordinator at (503) 229-5623 or toll free within Oregon at (800) 452-4011. People with hearing impairments may call the Oregon Telecommunications Relay Service at (800) 735-2900.

Public Hearing: Oregon Administrative Rule (OAR) 340-48-0032 (2) states that “The Corps provides public notice of and opportunity to comment on the applications, including the application for certification, provided that the department (DEQ), in its discretion, may provide additional opportunity for public comment, including public hearing.” Additional Section 401 process information is available on DEQ’s webpage (

Written comments: Written comments on project elements related to water quality must be received at the Oregon Department of Environmental Quality by 5:00 p.m. on the date specified in the upper right section on page one of this notice. Comments may be submitted electronically or through standard mail.

Email –

Mail – Oregon Department of Environmental Quality, Northwest Region
700 NE Multnomah Street, Suite #600
Portland, Oregon 97232
Attn: 401 Water Quality Certification Coordinator

WHAT HAPPENS NEXT: DEQ will review and consider all comments received during the public comment period. Following this review, certification of the proposal may be issued as proposed, issued with conditions, or denied. You will be notified of DEQ’s final decision if you submit comments during the comment period. Otherwise, if you wish to receive notification, please call or write DEQ at the above address. Public records can be accessed through the Your DEQ Online public records portal webpage 

ACCESSIBILITY INFORMATION: DEQ can provide documents in an alternate format or in a language other than English upon request. Call DEQ at (800) 452-4011 or email