Simulated runoff at many stream locations in the Methow River Basin, Washington

Open-File Report 2015-1011
Prepared in cooperation with the Bureau of Reclamation



A collaborative Bureau of Reclamation-U.S. Geological Survey (USGS) team has been brought together to incorporate a conceptual geomorphic-habitat model with a process-based trophic model to understand the processes important to stream habitat for anadromous fish populations. The Methow River Basin was selected as a test basin for this hybrid geomorphic-habitat/trophic model, and one of the required model inputs is long-term daily runoff at reaches with potential habitat. Leveraging the existence of a watershed model that was constructed for the Methow River Basin by the USGS, the team approached the USGS at the Washington Water Science Center to resurrect the original model and to simulate runoff at many locations in the basin to test the trophic model. Thirteen new flow-routing sites were added to the model, creating a total of 61 sites in the basin where daily runoff was simulated and provided as output. The input file that contains observed meteorological data that drives the watershed model and observed runoff data for comparisons with simulated runoff was extended from water year 2001 to water year 2013 using data from 18 meteorological sites and 12 observed runoff sites. The watershed model included simulation of 16 irrigation diversions that simulated 50-percent water loss through canal seepage. Irrigation was simulated as a constant application of 0.2 inches per day to during the irrigation season, May 1–October 7.

Comparisons of the simulated runoff with observed runoff at six selected long-term streamflow-gaging stations showed that the simulated annual runoff was within +15.4 to -9.6 percent of the annual observed runoff. The simulated runoff generally matched the seasonal flow patterns, with bias at some stations indicated by over-simulation of the October–November late autumn season and under-simulation of the snowmelt runoff months of May and June. Sixty-one time series of daily runoff for a 26-year period representative of the long-term runoff pattern, water years 1988–2013, were simulated and provided to the trophic modeling team.

Study Area

Publication type Report
Publication Subtype USGS Numbered Series
Title Simulated runoff at many stream locations in the Methow River Basin, Washington
Series title Open-File Report
Series number 2015-1011
DOI 10.3133/ofr20151011
Year Published 2015
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Washington Water Science Center
Description iv, 22 p.
Country United States
State Washington
Other Geospatial Methow River Basin
Datum North American Datum of 1983
Projection Universal Transverse Mercator projection
Scale 100000
Online Only (Y/N) Y
Additional Online Files (Y/N) N
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