UW Sprague R. Basin Conservation Practices Assessment

Project Overview

In the last several years, the Klamath River Basin has faced water shortages associated with the conflict of irrigation water demands and Endangered Species Act constraints, and exacerbated by drought. Current efforts by the NRCS to address these resource difficulties, as detailed in the Klamath Basin Adaptive Management Plan, focus on increasing water yield and storage, decreasing water demand, improving water quality and developing fish and wildlife habitat. Although basin-wide assessments of current resource conditions have been completed for a number of Klamath River sub-basins as part of the adaptive management effort, additional analysis -- based on the application of a distributed, process-based hydrologic model - may augment the evaluation of potential hydrological and water quality effects of the conservation practices and programs under consideration for the basin. The hydrologic model used for this study is the Distributed Hydrology and Vegetation Model (DHSVM) of Wigmosta et al. (1994).

Technical Objectives
The land management questions under study by the NRCS include the quantification of hydrologic and water quality changes arising from changes in irrigation method (primarily, switching from flood to sprinkler-based methods, forest management (e.g., thinning, juniper removal) and riparian zone restoration. One sub-basin of primary interest is that of the Sprague River (4,050 km2). DHSVM in its current form can be used to assess some, but not all, of these issues, in the Sprague River basin. Given these limitations, the specific technical objectives of this research are:

• To quantify the implications for the Sprague River hydrograph (timing and yield) and water balance of different scenarios of forest thinning, juniper control and of changes in irrigation methods and stream withdrawals.


• To investigate (survey) existing methods for assessing the water quantity and quality effects of conservation practices that lie beyond DHSVM's simulation capabilities, and recommend alternative approaches for further study.


• To develop and apply a scheme for aggregating results from the Sprague River basin (to which the above DHSVM analyses have been applied) to the entire Klamath River basin. Where more detailed DHSVM analyses are conducted for sub-portions of the Sprague River basin, an aggregation scheme may also be used to estimate results for the entire Sprague River basin.

Support
The funding for this project (nominally for 1 year) is provided by the Oregon National Resources Conservation Service (NRCS) as part of the broader Conservation Effects Assessment Project (CEAP), a USDA-led interagency effort to conserve the nation's watersheds, soil, and water resources. The objectives of CEAP are two-fold: first, to identify the optimal selection and placement of conservation practices to achieve specific water quality goals and other environmental aims; and second, to provide information important to assessing the economic benefit from implementing conservation practices.

References
Wigmosta, M.W., L. Vail, and D.P. Lettenmaier, 1994. A distributed hydrology-vegetation model for complex terrain, Water Resources Research, 30(6), 1665-1669.

Questions? Comments? Please email aww@hydro.washington.edu.
Last modified: Wed Oct 20 11:51:01 PDT 1999