Methow River Basin

Project Summaries


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9722-APK - Monitoring Water Resources and Simulating Water Management Alternatives in the Methow River Basin - Completed FY2003

Problem - Managing surface water and ground water in the Methow River Basin has proven challenging to local managers. State and federal agencies have established minimum flows throughout the basin for a variety of administrative actions related to water use to protect threatened and endangered Columbia River salmon. The administration of these minimum-flow targets requires ongoing monitoring of streamflow. Moreover, a major goal of water-resource managers is to avoid depleting streamflow during periods when minimum-flow targets are not being met and to reduce the frequency and duration of those periods.

Objectives - The first objective of this study is to continue monitoring streamflow and ground-water levels at existing stations throughout the Methow River Basin. The second objective is to examine the potential effects of water-management alternatives on streamflow in the Methow River Basin.

Relevance and Benefits - The proposed project supports the USGS mission to provide information on water resources for management activities and decisions. It also addresses water availability and ground-water/surface-water interactions, which are major water-resource issues identified in the Washington District's Science Plan. The project meets the USGS role to support other Department of the Interior bureaus by helping the U.S. Bureau of Reclamation achieve its management responsibilities. The USGS has already established the desired stream-gaging and ground-water monitoring networks in the basin and has constructed a watershed model of the basin.

Approach - The USGS will continue operation and maintenance of six stream gages, 15 monitoring wells, and one lake level station. The USGS will use the watershed model developed for the Methow River Basin to evaluate the effects of various water-resources management alternatives in the basin on achieving minimum-streamflow targets.

9722-AT8 - Analyzing aquifer and streamflow characteristics for artificial recharge in the Methow River Basin - Completed FY2003

Problem - The feasibility of artificial ground-water recharge depends on the availability of surface water for recharge, the infiltration capacity of the land surface, the hydraulic conductivity and storage capacity of the aquifers, and the residence time of ground water in an aquifer before it seeps back into a river. A current investigation of ground-water resources in the Methow River Basin by the U.S. Geological Survey (USGS) provides some of this information at a basin-scale, but a more detailed analysis is needed to characterize local ground-water flow and variations in aquifer properties, and determine when and by how much streamflows exceed regulatory flows.

Objective - The project has two objectives: to provide better resolution of aquifer properties and ground-water flow in selected areas of the Methow River Basin and to assess when and by how much streamflows exceed State regulatory flows in each area.

Relevance and Benefits - The proposed project complements the current USGS investigation in the Methow River Basin of the unconsolidated aquifer and its interaction with the river (Konrad and others, in review) by increasing the resolution of information about the unconsolidated aquifer in limited, but important, areas of the basin. In addition, the project will analyze streamflow records collected at a network of USGS stream gages with respect to regulatory flows. The project is consistent with Environment and Natural Resource Mission Goals of the USGS Strategic Plan 2000-2005 by developing hydrologic information that can assist in water-resources management decisions in the Methow River Basin. The approach will be readily transferable to other basins with similar management issues.

Approach - The first objective will be met by characterizing local aquifers in eight areas of the Methow River Basin by determining depth to the water table, ground-water levels and ground-water flow directions, and estimating ranges of hydraulic parameters. The analysis will be based on an existing data set of inventoried wells and proposed topographic surveys of floodplain areas. The second objective will be met by comparing the streamflow records from water years 1992 through 2001 with State regulatory flows at selected gages in the vicinity of each area.

9722-9EN - The Unconsolidated Aquifer and its Interaction with Surface Water in the Methow River Basin - Completed FY2003

Problem - Management of the water resources of the Methow River Basin (WRIA 48) is changing in response to the State-legislated watershed planning process and the listing of three species of fish under the Endangered Species Act (ESA). Management options have to be considered that minimize adverse effects on people but meet instream-flow needs for fish. Concerns over inadequate low flows may result in conversion from surface-water irrigation to ground-water irrigation. There are a number of unanswered questions regarding the ultimate effects: Does the discharge of artificially recharged ground water (from canal leakage and applied irrigation) affect surface-water low flows? Will conversion result in changes in low flows of significant magnitude to affect fish habitat? Does such ground-water discharge affect the temperatures of the surface water? Will conversion result in surface-water temperature changes that are significant to fish habitat? Will there be a significant degradation of ground-water quality with cessation of artificial recharge from surface-water irrigation systems? The same contaminant load (fertilizers, septic systems, etc.) will be present, but the amount of recharge will be diminished, presumably resulting in higher concentrations of contaminants. The ground-water system in the unconsolidated aquifer and its interaction with surface water must be defined to enable estimation of the potential impact of different management strategies prior to their implementation and for future use in development and implementation of a Methow River Basin watershed-management plan and a Habitat Conservation Plan.

Objectives - The objectives are: To describe the unconsolidated aquifer system in the Methow River Basin. To determine the nature of the interactions between surface water and the unconsolidated aquifer system. To establish a baseline of selected water-quality parameters in the unconsolidated aquifer.

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. As part of its efforts to effectively assess the Nation's ground-water and surface-water resources, the USGS collects basic data related to ground- and surface-water quantity, quality, and aquatic ecosystems. This and other information is used to understand and quantify how hydrologic systems respond to land-use, water-use, and climatic changes. 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 the environment. The Methow Basin epitomizes the Pacific Northwest's current water-management struggle to manage a limited water resource for irrigation while maintaining sufficient flows for fish that have been listed under ESA. This proposal compliments two other current USGS projects, which together will provide managers with a broad set of tools to manage the current and long-term water resources in the basin.

Approach - This investigation is planned for two phases to be conducted in cooperation with Okanogan County and the Methow River Basin Planning Unit. The first phase has been designed to: (1) describe the unconsolidated aquifer system at a basin-wide scale, (2) establish monitoring networks to collect data to evaluate the interactions of the ground and surface waters in the basin with emphasis on a single irrigation district, (3) construct and operate a ground-water scoping model which will be used to make initial estimates of the magnitude of these interactions, and (4) to collect baseline water-quality data to define the ground-water system. A second phase, (if necessary) will be conducted based on the results of Phase One.

9722-A4I - Surface-Water Hydrology in the Methow River Basin - Completed FY2003

Problem - 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 (ESA) and the State-legislated watershed-planning process (HB 2514). Management options have to be considered that minimize adverse effects on people but meet instream-flow needs for fish. Diversions of water from the river above existing and historical streamflow gages make it difficult to assess the natural streamflow conditions in the basin. To be able to estimate the impact of different management strategies throughout the basin prior to their implementation, a basin-wide watershed model is needed to estimate both the natural instream flow conditions and those that could result from different management options. At present, such a management tool does not exist.

Objectives - The objectives are to estimate natural daily streamflows and streamflow statistics at selected locations within the Methow River Basin; to quantify the effects of irrigation diversions and returns on the streamflows at selected locations within the Methow River Basin; and to provide a management tool for assessing the long-term effects of different management strategies on streamflow characteristics in the Methow River 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. As part of its efforts to effectively assess the Nation's ground-water and surface-water resources, the USGS collects basic data related to ground- and surface-water quantity, quality, and aquatic ecosystems. This and other information is used to understand and quantify how hydrologic systems respond to land-use, water-use, and climatic changes. 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. In the proposed study, the USGS will develop a hydrologic model that will assist watershed managers in assessing how much surface water is available naturally in the Methow River Basin, and how much surface water may be available for allocation.

Approach - This investigation will be conducted in two phases. In Phase One, an initial basin-wide watershed model will be built and calibrated to simulate daily discharges of natural streamflows at selected locations throughout the basin. In Phase Two, the ability of the initial model will be improved to allow for the simulation of more complex hydrologic features such as streamflow diversions and returns. Project-specific processors will be added to the model so it will be a user-friendly management tool. Results of Phase One and Phase Two will be documented in separate Water-Resources Investigations Reports.