OMAHA, NE - Heavy rain and mountain snowmelt runoff since the beginning of May have produced high flows along the South Platte River in Colorado and its contributing tributary streams. The three Denver-area dams operated by the U.S. Army Corps of Engineers, Omaha District and referred to as the Tri-Lakes Projects are Chatfield, Cherry Creek, and Bear Creek Dams.
These three reservoirs have captured a combined 25,000 acre-feet of flood water during this period. One acre-foot of water is equivalent to water covering one acre of land one foot deep. The combined storage capacity of these three reservoirs is nearly 314,000 acre feet of water.
The Omaha District routinely conducts inspections and monitors all three projects as a part of its Dam Safety Program. Surveillance frequencies are increased during periods of higher pools. All three projects are performing satisfactorily with no significant dam safety issues resulting from the recent rains and snowmelt runoff.
Without the Tri-Lakes Projects, the estimated water levels would have been one foot higher at the Denver streamgage on the South Platte River last weekend.
Cherry Creek and Chatfield Lakes rose about 3 feet and 8 feet, respectively, due to the higher inflows. Releases from both dams have been increased to evacuate stored flood water following lower downstream river stages. Since the inflows have dropped and the releases have been increased, the lakes have begun dropping. Evacuating the flood water stored at Cherry Creek is expected to be complete within the next week while Chatfield could remain in the flood pool for the next several weeks as the snowmelt runoff continues.
Bear Creek Lake, located on Bear Creek on the southwest edge of suburban Lakewood, Colo., has risen over 37 feet since May 1 due to heavy rain and snowmelt runoff. It is currently at pool elevation 5597.9 feet which occupies 30 percent of the flood pool. The reservoir is expected to stay in the flood pool for the next month as the snowmelt runoff continues.
As part of the system operation plan to evacuate flood storage, current releases from the Tri-Lakes dams are 500 cfs from Bear Creek Reservoir, 1900 cfs from Chatfield Reservoir, and 250 cfs from Cherry Creek Reservoir. These releases are coordinated with the State of Colorado Division of Water Resources. Releases were reduced last weekend during the threat of heavy rain to create channel capacity for local runoff downstream of the dams. All Tri-Lakes releases will continue to be adjusted based on reservoir and hydrologic conditions.
Pool elevation data for these and other Corps-operated dams, updated hourly, can be tracked online at http://www.nwd-mr.usace.army.mil/rcc/plots/plots.html#omaha_plots.
Public safety is a priority and the public is urged to rely on local emergency management officials for guidance regarding the flood response.