Water Resources Research Act Program

Details for Project ID 2018TN136B

Three-Dimensional Modeling of River Flows Under Extreme Weather Scenarios

Institute: Tennessee
Year Established: 2018 Start Date: 2018-03-01 End Date: 2019-02-28
Total Federal Funds: $19,998 Total Non-Federal Funds: $42,070

Principal Investigators: Jejal Bathi, Kidambi Sreenivas

Abstract: The proposed research is the development and application of a 3D hydraulic and water quality model using the tool named Environmental Fluid Dynamics Code (EFDC) for City of Chattanooga (the City) urban portion of Tennessee River below Chickamauga Reservoir, TN. The developed model will demonstrate the usefulness of three-dimensional simulations for watershed management under low flow (drought) and high flow (flooding) conditions. The river historic flows will be evaluated to determine flows and river levels for extremely low (low 5%) and extremely high (high 5%) flow periods and the model will be calibrated for these extreme conditions. The calibrated model will be used to simulate water quality under varied scenarios of extreme flows so that the pollutant fate and transport, reliability and availability of flows for water supply will be evaluated. More specifically, fate and transport of pollutants entering the river system because of persistent combined sewer overflows from the City areas will be assessed in order to estimate the spatial and temporal variability of river pollution and help assist to better manage drinking water utility intake operations, which is within the proposed model domain. In addition, understanding river flows, which will be achieved by proposed model, is critical for Tennessee Valley Authority (TVA) to manage releases from Chickamauga Reservoir, which is at immediate upstream of the proposed model boundary. As well, as part of this study, potential impact on identified critical infrastructure will be determined. For example, simulated critical velocity and bed scour at the bridge piers will be used to determine stress and hence the potential damage to the bridge stability. In addition, flood inundation of the critical infrastructure along the river banks will be evaluated using model simulated flood elevation under extreme high flow conditions. Overall, the proposed research is a demonstration study that will showcase usefulness and approach of using 3D computer models to help prepare river watershed management to prepare for possible extreme conditions that would cause devastating damage to critical infrastructure, environment and public health, if not prepared in advance.