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Posted 6/28/2010

Release no. 10-26-28


Des Moines, Iowa -- Increased inflow into the Saylorville Lake from its 5,823 square-mile watershed on the Des Moines River has caused pool levels to continue to rise.  In response to the National Weather Service’s 24-hour forecast, rainfall occurring over the Des Moines River watershed, and subsequent increased inflow into Saylorville Lake, the U.S. Army Corps of Engineers continues to release its maximum outflow from its conduit.

The Saylorville Lake level is currently at 878 feet and rising using approximately 70 percent of its available flood storage.  Inflow into the reservoir is expected to raise the pool level to 884.0 feet by Tuesday, June 29.  This level represents a pool level at the top of the spillway and 84 percent of flood storage capacity.  The Corps is raising the spillway’s inflatable dam (pneumatic crest gates) today to provide an additional six feet of spillway elevation to 890 feet.  The record high stage at Saylorville Lake was 892.03 feet on July 11, 1993.

Saylorville Lake’s inflow on Monday afternoon, June 28, is approximately 59,000 cubic feet per second (cfs) with an average outflow of 21,000 cfs.  Saylorville is currently storing 467,400 acre feet of water (152.3 billion gallons).

Forecast models indicate the lake level will surpass 890 feet on June 30 and continue to rise.  If forecasts continue to indicate the lake level will exceed 890 feet, the pneumatic crest gates will be lowered.  Combined outflows from the lake’s conduit and spillway could approach 43,000 cfs after lowering the crest gates.

Increased conduit releases are necessary to evacuate water storage as quickly as possible to accommodate the forecasted rise in inflow.  Reservoir discharge, combined with flows from tributaries below the reservoir will result in downstream flooding.  Residents in flood-prone areas along the Des Moines River watershed should be alert to rising water levels and begin preparation for higher water.

Updated information about Saylorville Reservoir is available on the web by visiting the Corps’ website at www.rivergages.com.  This web site includes links to the U.S. Army Corps of Engineers and National Weather Service websites that track Saylorville Reservoir elevations, Des Moines River flow and projected rainfall amounts.