By Larry Persily
Federal regulators have selected 15 rivers and creeks along the route of the proposed 807-mile natural gas pipeline from Prudhoe Bay to Nikiski — “representative waterbodies that support sensitive fishery resources’’ — for additional sediment transport modeling work by the Alaska Gasline Development Corp. (AGDC).
The assignment is part of the Federal Energy Regulatory Commission (FERC) review of AGDC’s plans for open-cut trenching to lay pipe at more than half of the 440-plus water crossings along the route. Regulators want to learn how pipeline construction may stir up sediment in the water and where the sediment might travel.
FERC sent its instructions to the state’s project team on May 31, responding to AGDC’s work plan for sediment transport modeling of open-cut water crossings. “After our review of the plan, we are requesting changes,” FERC said in its letter. Regulators recommended AGDC collect core samples at the proposed water crossings if the data is not otherwise available.