PUBLIC NOTICE
Alaska Department of Environmental Conservation (DEC)
Wastewater Discharge Authorization Program/§401 Certification
555 Cordova Street, Anchorage AK 99501-2617
Phone: 907-269-6285 | Email: DEC-401Cert@alaska.gov

Notice of Application for State Water Quality Certification

Public Notice (PN) Date: July 8, 2025                      PN Reference Number: POA-2020-00147-M1 v1.0
PN Expiration Date: August 7, 2025                                                    Waterway: Sagavanirktok River

Any applicant for a federal license or permit to conduct an activity that might result in a discharge into waters of the United States, in accordance with Section 401 of the Clean Water Act (CWA), must also apply for and obtain certification from the Alaska Department of Environmental Conservation that the discharge will comply with the CWA and the Alaska Water Quality Standards (18 AAC 70). The scope of certification is limited to the water quality-related impacts of the activity subject to the Federal license or permit (40 CFR 121.3, 18 AAC 15.180).

Notice is hereby given that a request for a CWA §401 Water Quality Certification of a Department of the Army Permit application, Corps of Engineers’ PN Reference Number indicated above has been received[1] for the discharge of dredged and/or fill materials into waters of the United States (WOTUS), including wetlands, as described below, and shown on the project figures/drawings. The public notice and related project figures/drawings are accessible from the DEC website at https://dec.alaska.gov/water/wastewater/.

To comment on the project or request a public hearing with respect to water quality, submit comments via (preferred method) DEC website https://dec.alaska.gov/commish/public-notices/ or email to the DEC email address: DEC-401Cert@alaska.gov with the subject line referencing Public Notice Reference Number: POA-2020-00147-M1 v1.0 or on or before the public notice expiration date listed above.

Applicant: Hilcorp Alaska, keri.iles@hilcorp.com keri.iles@hilcorp.com, 3800 Centerpoint Drive,#1400, Anchorage, AK 99503, (907) 777-8368; keri.iles@hilcorp.com

Project Name: Sagavarnirktok River Channel Maintenance

Dates of the proposed activity are planned to begin and end: 10/01/2025 to 11/30/2025

Location: The proposed activity is located within Section 3, T. 10N, R. 15E, Umiat Meridian, in North Slope Borough, Alaska. Project Site (Latitude, Longitude): 70.249850, -148.30494.

Purpose: The applicant’s stated purpose is to support and maintain the integrity of the bridge supports over the Sagavanirktok (Sag) River. The maintenance work is designed to support the integrity of the bridge supports and ensure adequate fish transport in the area surrounding the bridges. The maintenance is expected to decrease flood damage to infrastructure, including pipelines, roads, and production pads on the Sag River floodplain. Endicott Road is a vital transportation corridor and is the only summer vehicle access route for the Duck Island Unit.

Description of Proposed Work: The applicant states that the scope of this project is to improve flow under the Sagavanirktok (Sag) River vehicle bridge and pipe bridge by dredging and recontouring the river bottom to follow the natural slope of the riverbed. Seasonal flooding in the Sagavanirktok (Sag) River occurs annually and impacts the Sag River vehicle and pipeline bridges. This flooding deposits large quantities of silt and gravel immediately upstream and downstream of the bridges and causes scour depressions around the bridge's support structures.

The maintenance work is designed to support the integrity of the bridge supports and ensure adequate fish transport in the area surrounding the bridges. The maintenance is expected to decrease flood damage to infrastructure, including pipelines, roads, and production pads on the Sag River floodplain. Endicott Road is a vital transportation corridor and is the only summer vehicle access route for the Duck Island Unit.

This would be done by removing approximately 45,000 cubic yards of material from 13 acres of riverbed, focusing on excavating high areas down to 4 feet above sea level elevation and filling low areas to 4 feet above sea level elevation. Additional areas downstream of the bridges would be scoured to remove gravel that tends to plug the pump supplying water for Prudhoe Bay Operations Center (PBOC). Leftover material would also be placed in the bridge bulkhead area to replenish the east bank. Temporary gravel ramps on each bank would be constructed and used to remove material from the excavation areas and to help manage water flow to protect the work area during project execution. This project would begin in October 2025 and would be conducted during periods of lowest flow in the river. The anticipated timeline for the project is 45 days, with some variability depending on water levels. Sag River channel maintenance is required annually at this location.

The scope of this project is to improve water flow under the Sag River vehicle bridge and pipe bridge by recontouring the river bottom to follow the natural slope of the riverbed. This will be done by excavating high areas down to the 4 ft above sea level elevation and filling low areas back up to the 4 ft elevation. Additional area downstream of the bridges will be scoured to remove gravel plugging the pump supplying water for PBOC. Without remediation, the pump will become unusable. The details of the execution are as follows:

Recontouring of Sag Riverbed:

• Dredge approximately 13 acres of riverbed to remove approximately 45,000 cubic yards of gravel
• Dredged material will be spread over approximately 7 acres to flatten the river bottom
• Leftover material will also be placed on the opposite side of the vehicle and pipe bridges to replenish the bulkhead area of the east bank
• Typical equipment to be used for excavation and recontouring includes dozers and excavators of various sizes

Access Ramps:

• Construct a 100-foot by 50-foot temporary gravel ramp on the west bank of the Sag River using approximately 200 cubic yards of gravel
• Construct an additional 100-foot by 50-foot temporary gravel ramp on the east bank using approximately 200 cubic yards of gravel
• Gravel ramps will be used to remove material from the excavation area and manage water flow to protect the work area during project execution

Applicant Proposed Mitigation: The applicant proposes the following mitigation measures to avoid, minimize, and compensate for impacts to waters of the United States from activities involving discharges of dredged or fill material.

1. Avoidance: Hilcorp will prevent water quality degradation to the greatest extent possible by removing gravel from the Sag River during autumn months, when the river is at lowest flow. All appropriate BMPs will be implemented in accordance with permits, APDES general permit, and Hilcorp's approved SWPPP.
2. Minimization: Hilcorp will prevent water quality degradation to the greatest extent possible by removing gravel from the Sag River during autumn months, when the river is at lowest flow. All appropriate BMPs will be implemented in accordance with permits, APDES general permit, and Hilcorp's approved SWPPP.
3. Mitigation: Hilcorp will prevent water quality degradation to the greatest extent possible by removing gravel from the Sag River during autumn months, when the river is at its lowest flow. All appropriate BMPs will be implemented in accordance with permits, APDES general permit, and Hilcorp's approved SWPPP.

After reviewing the application, the Department will evaluate whether the activity will comply with applicable water quality requirements (any limitation, standard, or other requirement under sections 301, 302, 306, and 307 of the CWA, any Federal and state laws or regulations implementing those sections, and any other water quality-related requirement of state law). The Department may certify (or certify with conditions) with reasonable assurance the activity and any discharge that might result will comply with water quality requirements. The Department also may deny or waive certification.

The permit application and associated documents are available for review. To inquire about or request copies of the documents, contact dec-401cert@alaska.gov or call 907-269-6285.

Disability Reasonable Accommodation Notice

The State of Alaska, Department of Environmental Conservation, complies with Title II of the Americans with Disabilities Act (ADA) of 1990. If you are a person with a disability who may need special accommodation in order to participate in this public process, please contact ADA Coordinator Kristin Mabry, kristin.mabry@alaska.gov, 1-907-334-0884; or TDD Relay Service 1-800-770-8973/TTY or dial 711 at least 3 days prior to the expiration/closure date of this public notice to ensure that any necessary accommodations can be provided.

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