Following the closure of a 30-day public notice period, DEC has prepared an APDES proposed final individual permit for Hilcorp Alaska, LLC which operates the Endicott WaterFlood Operation - Hilcorp Alaska. Prior to making the final decision to issue the individual permit, DEC invites you to view the proposed final individual permit and associated documents. This review period is to allow the permittee the opportunity to review the proposed permit prior to final issuance. Comments from the general public were accepted during the Public Notice period of March 23, 2026 through April 24, 2026, and will not be accepted during this review period. You can access the documents on DEC’s Wastewater Discharge Authorization Program webpage at https://dec.alaska.gov/water/wastewater.

DEC Contact:   Amy Wockenfuss, (907) 269-8874, amy.wockenfuss@alaska.gov

Preliminary Draft General Permit Review Period:
Start Date: May 11, 2026                        
End Date: May 15, 2026 11:59 pm AKST/AKDT

Permit No: AK0038661

Proposed Permit Coverage: The proposed permit covers the discharge for Endicott Operations located on Duck Island in Stefansson Sound, Beaufort Sea, Alaska. The facility produces waterflood at a seawater treatment plant (STP) and distributes the waterflood for injection into oil producing formations to maintain formation pressures that enhances oil recovery. The authorized discharges include:

• Outfall 001A – Combined Outfalls 002A and 002B
  • Outfall 002A - STP and Potable Water (POW) Treatment Backwash
  • Outfall 002B - Domestic Wastewater
• Outfall 003A - Continuous Flush System

The combined discharge of the STP/POW (Outfall 002A) and Domestic Wastewater (Outfall 002B) through Outfall 001A includes the authorization of a chronic mixing zone for temperature, total residual chlorine (TRC), pH, and chronic whole effluent toxicity, as well as an acute mixing zone for TRC. There is no mixing zone authorized for Outfall 003A.

Tentative Determination: DEC has tentatively determined to reissue a discharge permit to the above listed applicant.

Administrative Record: The APDES preliminary draft permit, fact sheet, and associated documents are available for public review at the DEC offices located in Anchorage, Fairbanks, Juneau, Soldotna, and Wasilla. Please contact the office of your choice to arrange for hard copies of the documents to be available for your review.

555 Cordova Street; Anchorage, AK 99501; 907-269-6285
610 University Avenue;
P.O. Box 1800; Juneau, AK 99811-1800
Location: 410 Willoughby Street, Suite 303;
43335 Kalifornsky Beach Road;
1700 E Bogard Road #B, Suite #103;

If you would like to see any additional supporting technical documents, contact Amy Wockenfuss.

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.