Dale Hollow Lake Water Quality Modeling Study
Tennessee and Kentucky
Dale Hollow Lake, TN/KY is located in the Cumberland River basin and is operated and managed by the Nashville District Corps of Engineers. The project provides hydropower, flood control, water supply, recreation, and fish and wildlife enhancement. Low DO releases from the hydropower project are causing the tailwater to not meet state DO standards for coldwater fishery. Low DO releases are occurring more frequently than in the past, possibly as the result of changes in watershed land use.FTN calibrated the two dimensional water quality model CE-QUAL-W2 on Dale Hollow Lake and used it to evaluate options for improving water quality in the lake and in the tailwater. Regression analysis was used to develop temperature and water quality inputs for the CE-QUAL-W2 model. Preparation of model input involved analysis of physical, chemical, and biological data. Hydrologic data (measured inflows, back-calculated inflows, dam releases, pool elevations, precipitation, and evaporation) were analyzed to develop water budgets for wet, dry, and average years.
Arc View was used to map the reservoir and its sampling locations, locate depth transects measured by the District for use in developing the reservoir bathymetry input files for CE QUAL W2, determine tributary watershed sizes, and determine changes in land use occurring in the watershed between the 1970s and the 1990s. The ultimate use of this model is to provide insight into the elements affecting the reservoir water quality, and provide a tool to evaluate the effects of changes in watershed, point source, and reservoir management on the water quality in and downstream of Dale Hollow Lake. As part of developing CE-QUAL-W2 as a management tool, animation of the calibrated CE QUAL-W2 was provided to the District through the use of the Animation and Graphics Portfolio Manager CE QUAL W2 post-processor.
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