Title: Developing a Sediment Model for Use in the TMDL Processes in the Inland Northwest
Project Type: Research
Start Date: 01/03/2006
End Date: 02/28/2007
Congressional District: Washington 5
Focus Categories: Models, Sediments, Management and Planning
Keywords: TMDL, Modeling, Sediment, Nutrients, Winter runnoff, Erosion
Principal Investigator: Chen, Shulin (Washington State University )
Federal Funds: $23,000
Non-Federal Matching Funds: $46,099
Abstract: Sediment has been identified as a primary pollutant in the United States. Besides direct environmental impact, sediment is often the carrier for other pollutants such as nutrients and bacteria. Sediment allocation is thus an important component in many efforts of Total Maximum Daily Load (TMDL) development, including that in Washington State. However, mathematical models that are well accepted as technical tools for sediment prediction required in TMDL development are limited. This is primarily because the unique climatic winter conditions of the region. First, the erosion events in the inland Northwest are concentrated mainly in the winter seasons. Second, the frozen soil condition governs the major erosion generation event. Third, most existing models were developed for rainfall erosion event, whereas in the inland Norwest, snow melt caused erosion is quite often. Consequently, a well accepted technical tool for sediment related TMDL development in the inland Northwest is not available.
The aim of the proposed project is two folds: addressing an urgent need of the state agency (the Department of Ecology) and contributing to the science by advancing the existing knowledge. More specifically, the study fits well within the priority areas as it responds to the TMDL concerns (#5 focus area). The anticipated major result of the project is a modified mathematical model that can be used by the state agency and consulting communities in TMDL development processes. Efforts will be made after the project to disseminate the results including workshop and journal publications. The specific objective of the project is to modify the Modified Universal Soil Loss Equation (MUSLE) for application in the inland northwest to fit the regional winter conditions for use in TMDL development and watershed management. Specific research tasks include (1) implementation of MUSLE within a GIS environment on a subwatershed of Little Spokane River, (2) field equipment instillation and data acquisition, and (3) testing and modification of MUSLE with the data collected from the watershed.
The major uniqueness of the proposed research includes: (1) the modification of MUSLE model for application under winter erosion conditions including snow-melt driven erosion event, and as a result, (2) the recommendation of a verified technical tool for the state agency and the consulting community to used in TMDL process for sediment estimation. MUSLE is used in the SWAT (Soil and Water Assessment Tool) as the model for sediment simulations, and SWAT is widely used watershed modeling package for TMDL development. By providing a model that addresses the deficiencies of the existing ones, this project is to make an attempt toward satisfying the needs of the Department of Ecology and consulting communities for a technical tool for estimating sediment source in the processes of TMDL development and watershed management. Such an effort is timely with potential significant impacts upon not only to the state of Washington but to region with similar conditions.
The project will be conducted by a well qualified research team with adequate resources and experiences. The selection of the test watershed will allow the research team to take the advantage of an existing effort on TMDL development for Little Spokane River. Field data collection of the existing effort will provide additional information for testing the models, thus enhancing the project effort.
Progress/Completion Report, PDF