Salmon Creek Basin

Science Center Objects

Two reservoirs in the Salmon Creek Basin in north-central Washington store runoff from the upper basin for out-of-basin irrigation of farmlands. The U.S. Geological Survey (USGS), in cooperation with the Bureau of Reclamation (Reclamation), developed a precipitation-runoff model that simulates historical daily unregulated streamflows for different locations in the Salmon Creek Basin. The model can also be used to forecast daily unregulated streamflows for the runoff season (April-July) or longer periods as far as 1 year in the future. Reclamation plans to use the simulated historical daily unregulated streamflows for long-term-planning studies and may use forecasted daily streamflows to assist with seasonal planning of water operations.

9722-AV2 - Simulation of Unregulated Streamflows in the Salmon Creek Basin, Washington, in support of a Decision Support System - Completed FY2006

Problem - Two reservoirs in the Salmon Creek Basin, Conconully Lake and Conconully Reservoir, provide storage of water that is used to irrigate farmlands and enhance instream flows during low-flow periods. The source of water to the reservoirs is natural, unregulated streamflow discharge from the upper reaches in the basin. Currently, no tool exists to forecast the unregulated streamflows that would allow water-resource managers to optimize reservoir operations. The Bureau of Reclamation (Reclamation) has requested assistance from the USGS to create such a tool.

Objectives - The objective of this study is to create a tool that can be used to forecast daily values of unregulated streamflow discharge at selected points in the Salmon Creek Basin. The tool will be integrated by the RECLAMATION in a Decision Support System (DSS) that can be used to optimize reservoir operations in the basin.

Relevance and Benefits - An important part of the USGS mission is to provide scientific information to manage the water resources of the Nation, and to enhance and protect our quality of life. The understanding of the hydrologic-system response is used by watershed managers to design water-supply and land-management options that optimize the quantity and quality of water resources for both people and nature. The study is an interagency Department of the Interior effort that fits the objective of the USGS Strategic Plan to develop DSSs, and it also fits the objective of the Science Plan of the Washington Water Science Center to understand watershed systems.

Approach - Existing hydrological and meteorological data will be compiled and used to construct and calibrate a watershed model for the Salmon Creek Basin. Initial model parameters will be obtained from a watershed model recently created by the USGS for the adjacent Methow River Basin. The Salmon Creek Basin watershed model will be calibrated and tested, and transferred to the RECLAMATION for its use and completion of the DSS. A USGS Water-Resources Investigations Report will be published that documents model construction, an error analysis of results, and model limitations. The report will also describe how the watershed model fits into the DSS.