State proposes more riverbed for Alyeska to protect buried pipeline near Coldfoot

The state proposed Wednesday to add about 2.6 acres of the Middle Fork Koyukuk River to the trans-Alaska pipeline's lease, so Alyeska Pipeline Service Company can build a rock structure where the river is wearing away toward the buried pipe.

The crossing is about 30 miles north of Coldfoot. River erosion upstream "is now encroaching on the buried pipe," the state Department of Natural Resources wrote in its analysis and proposed decision. Over the past decade, the river's channel has shifted and eaten into its banks, pushing more of its flow along the north side, the analysis says.

Alyeska wants to build a buried rock structure, called a sill, in the riverbed downstream of the pipe, and fill a nearby low spot with gravel.

State Pipeline Coordinator Anthony Strupulis found the change in the state's best interest and said its effect on state resources would be negligible. Written comments are due by 5 pm Dec. 4, under the public notice. No one commented when the state first gave notice of the application in August.

It isn't the first fix proposed at this crossing. In May 2023, the Bureau of Land Management approved a rock revetment, a layer of rock armoring the riverbank, upstream of the pipe at the same spot, describing the erosion in nearly the same words. Neither Alyeska's 2026 application nor the state's analysis mentions it, and the records don't say whether it was built.

Alyeska's application calls the river "an anadromous fish stream," meaning salmon or other fish migrate up it from the sea. The state's analysis doesn't discuss fish, and says Alyeska must get any other permits it needs. The state Department of Fish and Game said in September that work in fish-bearing waters requires a Fish Habitat Permit. State records don't show whether one has been issued for this work.

In 2023, a BLM fish biologist wrote that the earlier project would affect essential fish habitat. BLM also said Wiseman and Coldfoot residents use the area for subsistence, but found that project wouldn't reduce the fish or wildlife available to them.

The records also disagree on the details. Alyeska's August drawing shows the sill at about 400 feet long. A September drawing in the state's analysis shows it at about 700 feet. Neither explains the change.

The timing has shifted, too. Alyeska said in June that work could start as early as July, and in August that it was scheduled for August or September. The state's analysis now lists April 15, 2027, for about 10 days of work. A state permit for a temporary construction area on land nearby has been in effect since Aug. 24. The records don't show whether any work has happened.

Alyeska has sought similar rock work this year on the Sagavanirktok River, where the river keeps chewing toward the pipeline, Alaska News reported July 30.