Precipitation-runoff simulations of current and natural streamflow conditions in the Methow River Basin, Washington

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Title Precipitation-runoff simulations of current and natural streamflow conditions in the Methow River Basin, Washington
Creator Ely, D. Matthew
Subject Computer simulation; Runoff; Precipitation (Meteorology); Streamflow
Spatial Coverage Columbia River; Washington
Description Management of the water resources of the Methow River Basin is changing in response to the listing of three species of fish under the Endangered Species Act and the Washington State-legislated watershed-planning process. This report describes the construction and calibration of an enhanced precipitation-runoff model for the Methow River Basin and evaluates the model as a predictive tool for assessing the current and natural streamflow conditions. This study builds upon a previous precipitation-runoff model for the Methow River Basin and validates the current model using a new, more extensive streamflow data network. The major enhancement was the simulation of current flow conditions with the addition of irrigation diversions, returns, and application. The Geographic Information System Weasel characterized the physical properties of the basin and the Modular Modeling System, using the Precipitation-Runoff Modeling System, simulated the hydrologic flow. Streamflow was simulated for water years 1992-2001 to calibrate the model to measured streamflows. A sensitivity analysis was completed using nonlinear regression to determine hydrologic parameters pertinent to the modeling results. Simulated and measured streamflow generally showed close agreement, especially during spring runoff from snowmelt. Low-flow or baseflow periods, most restrictive to fish habitation, were simulated reasonably well yet possessed the most uncertainty. Simulations of annual mean streamflow as a percentage of measured annual mean streamflow for the 10-year calibration period at six of the seven streamflow gaging stations ranged from -35.2 to +26.2 percent, with 65 percent of the simulated values within 15 percent. One station was intentionally calibrated to over-simulate discharge (simulated discharge greater than measured discharge) in order to compensate for observed channel lossesnot simulated by the model. Simulation of water years 1960-2001 demonstrated great variability in monthly streamflow statistics. The simulated mean monthly flows for 11 streamflow-gaging stations were an average of 2.5 percent higher for water years 1992-2001 than for the entire simulation period. If water year 2001, an extreme drought year, is omitted, simulated mean monthly flows for the 11 streamflow-gaging stations were an average of 9.0 percent higher than for the entire simulation period. The calibrated model also examined the effects of irrigation-canal seepage on streamflow. Irrigation-canal seepage contributed to streamflow throughout the year, with the greatest effect during the irrigation season.
Publisher U. S. Geological Survey
Contributors Okanogan County
Date 2003
Type Text
Format application/pdf
Digitization Specifications pdf file copied from USGS website (http://pubs.usgs.gov/wri/). Uploaded into CONTENTdm version 3.7.
Identifier http://pubs.usgs.gov/wri/wri034246/
Source Ely, D. Matthew, 2003, Precipitation-runoff simulations of current and natural streamflow conditions in the Methow River Basin, Washington, Washington: U.S. Geological Survey Water-Resources Investigations Report 03-4246, 43 p.
Language eng
Rights Management Public Domain, Courtesy of the USGS
Holding Institution University of Utah
Metadata Cataloger Daureen Nesdill; Kristin Willmore
ARK ark:/87278/s63r0rsf
Setname wwdl_er
Date Created 2004-11-01
Date Modified 2005-10-06
ID 1145712
Reference URL https://collections.lib.utah.edu/ark:/87278/s63r0rsf
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