Tennessee Valley Authority (TVA) Reservoir Modeling

Riverside Technology, inc. (RTi) worked with Michael Baker, Jr., Inc. engineers under contract to the Tennessee Valley Authority (TVA) to perform reservoir modeling and flood frequency analysis for 36 reservoirs within the Tennessee and Cumberland River basins. The goal of the project was to assess how different reservoir operating policies could impact flood risk, hydropower revenues, navigation on the river, water supply and quality, and recreational activities. TVA operates the individual reservoirs for combinations of flood control, navigation, power generation, and enhancement of environmental quality along the river. The complexity of individual reservoir operations is compounded as TVA operates many of the reservoirs jointly, holding flood waters in tributary projects until the mainstem reservoirs can safely release the flood flows, often after the peak of the storm has passed.

RTi’s primary role in the project was modeling the TVA system using the University of Colorado’s RiverWare® river basin model. RTi’s RiverWare® model of the TVA system accounts for all of the individual reservoir operations as well as the feedback mechanisms between mainstem reservoirs and the tributary systems. The RiverWare® model implemented by RTi for TVA is one of the largest and most complex RiverWare® applications ever built. The model was run at a 6-hour time step for a 99-year period.

RTi ran the model using historical natural flows for the entire period, and then performed a flood frequency analysis on annual and seasonal peak discharges or elevations generated by the model. TVA provided alternative reservoir operating scenarios and results of those runs were compared to the base line model to identify potential changes in flood risk, hydropower revenues, and recreational opportunities. The results of the study became part of a larger Environmental Impact Statement developed by TVA to examine impacts of changes in operational policies.

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