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Project ID:2006OR76B

Title: Modeling Effects of Channel Complexity and Hyporheic Flow on Stream Temperatures

Project Type: Research

Start Date: 02/15/2006

End Date: 02/14/2007

Congressional District: 1

Focus Categories: Hydrology, Models, Surface Water

Keywords: Water quality modeling, water temperature, channel complexity, hyporheic flow

Principal Investigator: Wells, Scott

Federal Funds: $20,194

Non-Federal Matching Funds: $40,225

Abstract: Stream temperatures are affected by multiple forcing functions, including surface heat exchange (including solar radiation, evaporation, conduction, and net long wave radiation) and hyporheic flows. Each of these forcing functions is directly influenced by the level of channel complexity in the stream channel and riparian shading. Knowing that stream channel complexity has diminished over time in the Willamette basin, an important question to consider is "what were stream temperatures before we altered the natural channels?" This is an important issue in determining what natural conditions were and how we have strayed from these so-called "natural" conditions as a result of channelization, dam building, and changes to the riparian vegetation and deforestation. The current Oregon DEQ temperature TMDL relies on determining a "natural" condition. In order to develop an understanding of what that is, a hydrodynamic and water quality computer simulation model will be applied to the Willamette river with several levels of channel complexity and varying rates of hyporheic flows. Adapting the model used to develop total maximum daily loads (TMDL) for temperature in the Willamette River, the effects of present and past channel complexity on water temperatures will be determined. The model used to develop the TMDL was the Corps of Engineers dynamic 2-D model CE-QUAL-W2, which consists of directly coupled hydrodynamic and water quality transport models and simulates parameters such as temperature, algae concentration, dissolved oxygen concentration, pH, nutrient concentrations and residence time. The model also incorporates a dynamic shading algorithm for both vegetative and topographic shading on water bodies. A comparison of model results will indicate whether a more complex channel configuration will reduce stream temperatures provided streamside vegetation provides sufficient shade cover.

Progress/Completion Report, PDF

U.S. Department of the Interior, U.S. Geological Survey
Maintained by: John Schefter
Last Updated: Thursday, January 03, 2008
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