Subjecting Lake Pend Oreille to fluctuating water levels aimed at increasing downstream power generation will erode shorelines, hurt water quality and destroy valuable wetlands at Idaho’s largest lake, the Idaho Conservation League said in a lawsuit.
The suit was filed against the Bonneville Power Administration in the 9th Circuit Court of Appeals last week. It targets the variable winter water levels in the lake, which have been unpopular with local residents.
Lake Pend Oreille, known for its recreational appeal, covers nearly 95,000 acres. Raising and lowering its water levels by up to 6 inches per day during the winter could generate millions of dollars in downstream electrical output, according to the BPA.
The lake’s levels are controlled by Albeni Falls Dam on the Pend Oreille River, which is a tributary of the Columbia. The flow passes through multiple hydroelectric dams before it reaches the ocean.
After 20 years of operating with stable winter lake levels, the BPA adopted a plan in late 2011 that would allow for more variation.
The Idaho Conservation League said the BPA violated federal law by failing to do a thorough environmental review of how fluctuating winter lake levels would affect shoreline erosion and habitat. Bank erosion has been a problem since Albeni Falls Dam went into operation in 1957, according to the lawsuit, which said that adding winter fluctuations would make a bad situation worse.
“The lake is obviously an important resource for our community,” said Brad Smith, an Idaho Conservation League associate.
He said the league’s objective is to get the BPA to pay for mitigation for past resource damage from the dam, and conduct a thorough analysis of changing the winter lake levels.
The erosion is detrimental in various ways, the lawsuit said. Water quality in the lake and Pend Oreille River is diminished by sloughing banks, which increase the amount of nutrients in the water and promote algae growth, the suit said. The loss of valuable wildlife habitat is also a concern, Smith said.
Lake Pend Oreille and the Pend Oreille River lost more than 6,000 acres of wetlands and river deltas when Albeni Falls Dam went into operation, the lawsuit said.
The lake is an important stop for migrating waterfowl on the Pacific Flyway. The Clark Fork River delta in Lake Pend Oreille also provides important waterfowl habitat, but it’s losing acres per year to erosion from the operation of Albeni Falls Dam, the suit said.
BPA officials declined to comment on the suit Wednesday.