Corps lakes providing water supply and water quality releases due to drought

Published Oct. 9, 2012

(Oct. 9, 2012) The Rock Island District, U.S. Army Corps of Engineers, is currently operating its three Iowa reservoirs for drought conditions. With significantly decreased inflows, Saylorville Lake at Des Moines, Iowa; Lake Red Rock at Knoxville, Iowa; and Coralville Lake at Iowa City, Iowa; continue to release water to provide water supply and water quality for communities and utility needs downstream of the reservoirs.

Average outflow at 9 a.m., Oct. 9, was 224 cubic feet per second (cfs) at Saylorville Lake, 324 cfs at Lake Red Rock, and 150 cfs at Coralville Lake. Minimum outflows will be maintained for as long as needed to ensure water supply and water quality below the reservoirs.

With outflows exceeding inflows into the reservoirs, pool levels will gradually lower. In the absence of significant rainfall pool levels are projected to drop ½ foot to 2 feet per month. The 9 a.m. pool level at Saylorville was 833.97 feet; at Lake Red Rock, 741.94 feet; and at Coralville Lake, 682.62 feet.

Lake users should use caution in the upper portions of the lakes and along the shorelines as pool levels will be lower than normal. Decreased inflows and lower lake levels may also prevent fall pool raises to accommodate migrating bird species and provide fish and wildlife benefits.

Drought operations will continue until reservoir inflows exceed target downstream release rates and the reservoirs return to normal conservation pool levels. The conservation pool levels are: Saylorville Lake, 836 feet; Lake Red Rock, 742 feet; and Coralville Lake, 683 feet.