Folsom Dam operator will float pumps if lake drops too low

Diagram of temporary floating pump system shared by the Bureau of Reclamation(Photo: Bureau of Reclamation)

FOLSOM – The Bureau of Reclamation is preparing a barge with 11 floating pumps to continue providing tap water to hundreds of thousands of people if the level of Folsom Lake drops below the water supply outlet built into the dam.

“We’re just making a prudent decision now based on what could happen,” Bureau spokesperson Erin Curtis said.

The Bureau first began considering floating pumps last year as the lake approached a record low level of 357 feet above sea level — just 40 feet above the center of the outlet that provides domestic water to the cities of Roseville and Folsom, Folsom Prison and the San Juan Water District.

The plan was shelved when late season rain and snowmelt brought the lake level up 68 feet by early May.

The Placer County Water Agency said it has a “grave concern” that a state order last week to conserve cold water supplies in Shasta Lake to protect winter-run salmon will lead to expanded releases from Folsom Lake that by late summer or early fall could drop the lake to a new record low level within feet of the outlet.

“We could see a half million people in the region without water,” PCWA general manager Einar Maisch said in a prepared statement.

The temporary floating pump system would prevent the taps from going dry, reaching water at least 90 feet below the permanent supply outlet, according to a diagram provided to News10 by the Bureau of Reclamation.

The diagram shows the barge near the center of American River channel about 400 feet upriver from the dam where the old river bed is about 225 feet above sea level.

The pumps would be powered by a land-based power supply and the lake water would be pumped through a pipeline running over the dam through a trench cut in the road before entering the permanent supply system near the existing pumping plant below the dam.

Curtis said the Bureau was still working on alternate arrangements to conserve Folsom Lake water so that it wouldn’t need to deploy the floating pump system.

“We’re not sure it will be necessary but we know that it’s a possibility,” she said.