Corps of Engineers Omaha District Forecast Update Brian Twombly Kellie Bergman January 2010 Jay Lincoln
Volumetric Water Supply Forecasts • Bureau of Reclamation projects • Joint-use/flood control storage needed for expected runoff volume • Clark Canyon Dam, MT 50,000 acre-feet • Canyon Ferry Dam, MT 795,000 acre-feet • Tiber Dam, MT 260,000 acre-feet • Boysen Dam, WY 145,000 acre-feet • Yellowtail Dam, WY 240,000 acre-feet • Informational purposes only • Glendo Dam, WY
Multi-Variable Linear Regression • Computing April to July “natural” inflow volume to the project. • Independent predictor variables: • Antecedent conditions • The basin average snow water equivalent (SWE) • Spring-season precipitation
Example of Volumetric Water Supply Forecast (Canyon Ferry Reservoir) IF = 2.023(ANTON) + 0.177(SAPR) + 0.265(PREAMJ) - 3.081 • IF = The forecasted natural April through July inflow volume to Canyon Ferry in MAF. • ANTON = The natural October and November antecedent runoff volume in MAF. • SAPR = The average April 1 snowpack water content in inches of 9 snotel stations. • PREAMJ = The average monthly precipitation in inches for 9 stations for each month of April, May, and June.
Model Development Using ARRA Funding • Modeling is overseen by the USACE Hydrologic Engineering Center • West Consultants in San Diego, CA • Modeling three different locations: • Chatfield Dam in Denver, CO • Fall River near Hot Springs, SD • James River upstream of Lamoure, ND
Fall River Basin, HEC-HMS models for the Cold Brook and Cottonwood Reservoir Basins.
James River Basin, HEC-HMS models for the Jamestown Reservoir Basin and downstream of the reservoir to Lamoure, ND.
Chatfield Dam, HEC-HMS models for the Chatfield Basin and downstream to the Henderson Stream Gage in the South Platte River and HEC ResSim model for Chatfield Reservoir.