USGS Publications—Open-File Report 2005-1430
In cooperation with DuPage County Stormwater Management Division
Open-File Report 2005-1430
By David E. Whitbeck
Open-File Report 2005-1430 is available in pdf format and is 774K in size.
If you have Adobe® Acrobat® or Adobe® Acrobat® Reader® installed on your computer, you may view and print the PDF version of this report. Acrobat Reader can be downloaded for free from Adobe Systems, Inc.
The Lamoreux Potential Evapotranspiration (LXPET) Program computes potential evapotranspiration (PET) using inputs from four different meteorological sources: temperature, dewpoint, wind speed, and solar radiation. PET and the same four meteorological inputs are used with precipitation data in the Hydrological Simulation Program–Fortran (HSPF) to simulate streamflow in the Salt Creek watershed, DuPage County, Illinois. Streamflows from HSPF are routed with the Full Equations (FEQ) model to determine water-surface elevations. Consequently, variations in meteorological inputs have potential to propagate through many calculations. Sensitivity of PET to variation was simulated by increasing the meteorological input values by 20, 40, and 60 percent and evaluating the change in the calculated PET. Increases in temperatures produced the greatest percent changes, followed by increases in solar radiation, dewpoint, and then wind speed. Additional sensitivity of PET was considered for shifts in input temperatures and dewpoints by absolute differences of ±10, ±20, and ±30 degrees Fahrenheit (°F). Again, changes in input temperatures produced the greatest differences in PET. Sensitivity of streamflow simulated by HSPF was evaluated for 20-percent increases in meteorological inputs. These simulations showed that increases in temperature produced the greatest change in flow. Finally, peak water-surface elevations for nine storm events were compared among unmodified meteorological inputs and inputs with values predicted 6, 24, and 48 hours preceding the simulated peak. Results of this study can be applied to determine how errors specific to a hydrologic system will affect computations of system streamflow and water-surface elevations.
For more information contact the project lead Audrey Ishii.
Or
Science Center DirectorVisit the USGS Illinois Water Science Center Web Site at http://il.water.usgs.gov/
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://pubs.water.usgs.gov/ofr20051430
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Page Last Modified: Saturday, 12-Jan-2013 21:59:35 EST
