State proposes adding Koyukuk riverbed to pipeline lease for rock sill at milepost 208

State Pipeline Coordinator Anthony Strupulis proposed Wednesday to add about 2.63 acres of Middle Fork Koyukuk riverbed to the trans-Alaska pipeline lease. The addition would make room for an Alyeska Pipeline Service Company rock sill at pipeline milepost 208, about 30 miles north of Coldfoot.

Scour upstream "is now encroaching on the buried pipe," the state Department of Natural Resources' analysis and proposed decision said. Over the past decade, it said, bank erosion from channel changes has concentrated flow along the north bank. Alyeska proposes a buried rock sill downstream of the pipe and gravel fill in a nearby depression.

Strupulis found the amendment in the state's best interest and not significant, saying the impact on state resources would be negligible.

Written comments are due by 5 pm Dec. 4, under the public notice. No one commented after the state's August notice of the application.

The state's records and Alyeska's differ on the details. Alyeska's August drawing labels the sill about 400 feet long, with 1,400 cubic yards of rock. A September drawing in the state's analysis labels it about 700 feet and leaves out the sheet that lists rock. Neither document explains the change. Both say the structure may be extended south in the fall.

The start date has also moved. Alyeska's June narrative said work could start as early as July 6. Heather Lescanec, Alyeska's land and right-of-way lead, wrote in August that it "is scheduled to begin this August or September." The state's analysis lists April 15, 2027, for about 10 days of work. A state land use permit for a temporary upland construction area has been in effect since Aug. 24. The records do not show whether any work has happened.

Alyeska's narrative calls the river "an anadromous fish stream." The state's analysis does not discuss fish, saying Alyeska must secure other required permits. Fish and Game said in a September evaluation of the pipeline lease renewal that work in fish-bearing waters requires a Fish Habitat Permit. State records do not show whether one has been issued for this work.

This is not the first fix proposed at the crossing. In May 2023 the Bureau of Land Management authorized a rock revetment upstream of the pipe at the same location, on 3.5 acres, describing the scour in nearly the same words. Neither Alyeska's 2026 narrative nor the state's analysis mentions it, and the records do not say whether it was built.

BLM fish biologist David Esse wrote then that "There would be impacts on essential fish habitat (EFH) from the proposed action." BLM also said Wiseman and Coldfoot residents use the area for subsistence, and found the 2023 work would not reduce fish or wildlife available to them.

Alyeska has sought similar rock work this year on the Sagavanirktok River, as Alaska News reported July 30.