USGS Washington Water Science Center
|Project Home | Publications and Products | Maps | Project Summaries | Partnerships ||
9722-9F1 - Salmon River Watershed Analysis - Completed FY2003
Problem - Watershed analysis, a cornerstone of salmon-recovery efforts in the Pacific Northwest, is commonly hampered by a lack of adequate hydrologic characterization. For example, stream low-flow magnitude and frequency bear important implications for fisheries management, yet, streamflow records for many salmon-bearing streams either do not exist or are insufficient to permit reliable characterization of extreme low flows. The Quinault Indian Nation is undertaking an interagency, collaborative watershed analysis of the 34-square-mile Salmon River watershed to assess impacts that human activities of the industrial age have had on the watershed and to plan for the future. As is the case for many small Pacific Northwest watersheds, available hydrologic data for the Salmon River are insufficient for reliable low-flow characterization. The aims of the proposed investigation are to contribute to the hydrologic assessment of the watershed and to demonstrate to the community of watershed practitioners in the Pacific Northwest how a limited program of field measurement can be used in conjunction with the extensive USGS historical data bases to characterize low flows for ungaged streams such as the Salmon River.
Relevance and Benefits - Objectives and goals of this investigation are consistent with directions given by "Strategic Directions in WRD Scientific Activities" (SDWRDSA), WRD Memorandum 98.21: "Priority Issues for the Federal-State Cooperative Program (WRD98.21), WRD Memorandum 95.44: "Avoiding Competition with the Private Sector" (WRD95.44), and the USGS Washington Water Science Center Science Plan (WASCI99).
Participation in watershed analysis of the Salmon River watershed under the President's Northwest Forest Plan involves several diverse tasks: (1) review and presentation of the existing scientific information concerning hydrologic effects of road construction and forest harvesting in the Pacific Northwest; (2) application of this current knowledge within the context of the Salmon River watershed; (3) evaluation of impacts of forest management and other human activities on the distribution wetlands; (4) compilation of existing hydrological and meteorological data from diverse sources for the watershed; and (5) estimation of stream peak and low flows, where the latter is to be accomplished using novel techniques. Thus, participation is prescribed by SDWDSA Priority Issues 1, 2, and 4; by broader USGS goals 3, 6, 7, and 8 as outlined in WRD95.44; and Issues 1 "Watershed Assessment Methods" and 2 "Ground Water/Surface Water Interactions" of WASCI99.
Development, testing, and application of a novel technique for describing low-flow characteristics that will be applied to the Salmon and nearby rivers is an activity of the type prescribed by broader USGS goals 2 and 3 outlined in WRD95.44, and by Issue 1 "Watershed Assessment Methods" of WASCI99.
Finally, USGS contributions to the watershed analysis of the Salmon River watershed will serve as an up-to-date information reference for the U.S. Forest Service and for the Quinault Indian Nation as they develop forest, fisheries, and wildlife management plans for the Salmon River watershed.
Approach - Participation in the watershed analysis will be conducted by participating in meetings with watershed team members and by addressing the hydrologic issues for the watershed to the extent permitted by historical records and other sources of data, and by inference to hydrologic literature for similar forested watersheds. The base-flow predictive models will be developed through correlation of 12 monthly measured discharges on the Salmon River with continuous discharge as gaged on a nearby river. A case for the reliability of base-flow predictive models that are developed from a single season of measurements will be made by developing and testing a similar model using data from concurrently operated, continuous-discharge stations on two rivers that drain the Pacific Slope of the Olympic Peninsula. The low-flow investigation will provide an example to future watershed analysts of how to characterize low-flow regimes for ungaged systems on the basis of brief field investigations and historical records from nearby rivers. If the number of continuously gaged rivers in the region declines, as it has declined during the past 20 years, hydrologic methodologies that take advantage of the wealth of historical data that has been amassed from USGS stations could become integral to watershed analysis.