Corps of Engineers Raises Coralville Lake Outflows

Published June 30, 2010

Iowa City, Iowa -- Increased inflow into Coralville Lake from its 3,084-square-mile watershed on the Iowa River continues to raise pool levels.  In response to rainfall occurring over the Iowa River watershed; subsequent increased inflows into Coralville Lake; requests from the cities of Iowa City and Coralville, and the University of Iowa; and the potential for additional rainfall over the next several weeks, the U.S. Army Corps of Engineers is increasing outflows from Coralville Lake.

Lake discharges have been increased from 6,000 cfs to 8,000 cubic feet per second (cfs) on June 30 to gain additional flood storage as quickly as possible.  Lake discharge, combined with flows from tributaries below the lake may result in localized downstream flooding.  Residents in flood-prone areas along the Iowa River watershed should be alert to rising water levels.

The Coralville Lake level on Wednesday afternoon, June 30, is 703.90 feet and rising using approximately 56 percent of its available flood storage.  Coralville Lake’s current average inflow is approximately 9,000 cfs.  With the increase in outflow from 6,000 cfs to 8,000 cfs the lake is forecast to peak on July 8 near 705.5 feet (spillway crest is 712.0 feet) using 62 percent of its available flood storage.  The record high stage at Coralville Lake was 717.02 on June 15, 2008. Coralville Lake is currently storing 248,510 acre feet of water (80.97 billion gallons).

Updated information about Coralville Lake is available on the web by visiting the Corps’ websites at and  These web sites include links to the U.S. Army Corps of Engineers and National Weather Service websites that track Coralville Lake elevations, Iowa River flow and projected rainfall amounts.

Release no. 10-06-32