FERC approves remaining environmental studies for Alaska’s 600-MW Susitna-Watana

The Federal Energy Regulatory Commission has approved the remaining 14 environmental studies for the 600-MW Susitna-Watana hydroelectric project, ensuring the project on Alaska’s upper Susitna River can keep to schedule.

FERC staff ruled in December that applicant Alaska Energy Authority’s revised study plan for the project lacked sufficient detail about 14 of Susitna-Watana’s 58 proposed environmental impact studies. As the start of the FERC licensing process, the plan proposed 58 individual studies of the proposed dam site and surrounding area, 184 miles up the Susitna River above Devils Canyon.

In January AEA convinced FERC to accelerate its revised study plan schedule for the 14 studies so that AEA would not lose the entire 2013 field season for the studies of the Susitna-Watana project (No. 14241).

FERC approved in April one of the remaining study plans without modification and the other 13 with modifications. The studies cover water quality monitoring, mercury assessment and potential for bioaccumulation, geomorphology, fluvial geomorphology modeling below Watana Dam, groundwater, ice processes in the Susitna River, fish and aquatics instream flow, riparian instream flow, fish distribution and abundance in three Susitna reaches, river productivity, characterization and mapping of aquatic habitats, and riparian vegetation downstream from Watana Dam.

“AEA remains confident in the Susitna-Watana Hydro Revised Study Plan,” Project Manager Wayne Dyok said. “These approvals come after an intensive, year-long effort by over a hundred individuals, dozens of agencies, and a variety of stakeholders.”

FERC rejects agencies’ call for longer study schedule

In approving plans for the last 14 studies, FERC also rejected calls from resource agencies and groups to expand AEA’s proposed two years of studies to cover five years. The National Marine Fisheries Service, the U.S. Fish and Wildlife Service, and numerous individuals and non-governmental organizations expressed concerns that two years of sampling biotic communities and physical processes is not enough to collect adequate data.

“AEA’s proposed two-year study schedule is consistent with generally accepted practices in the scientific community for evaluating the effects of hydropower projects on fisheries and riparian resources…” the FERC ruling said. “Therefore, it would be premature to require additional years of data collection without first evaluating the data and modeling results that will be obtained from 2013 and 2014 study seasons. The need to conduct additional years of studies will be determined on a case by case basis for each study.”

AEA plans to apply for a FERC license for construction in 2015 according to the project’s original timeline. Assuming AEA’s plan progresses as hoped, the authority said the project could be online by 2024.

AEA took bids in 2012 for an independent construction cost estimate for the project. Susitna-Watana includes a concrete gravity or rockfill dam of from 700 to 800 feet tall and a crest length of at least 2,700 feet. It would create a 39-mile-long reservoir 90 river-miles northeast of Talkeetna, Alaska.

Based on ongoing feasibility studies, the project’s capacity could be as large as 800 MW. Power is to be transmitted north to the interior and south to south-central Alaska along new and existing transmission lines.

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