Third-Fourth Creeks Flood Mitigation (TN, USA)

DSI was contracted by Knox County and the City of Knoxville to perform hydrologic and hydraulic modeling studies to address flood mitigation and sedimentation issues in two watersheds of the Upper Tennessee River basin. Using Knox County and City of Knoxville GIS data for the watershed with DTM_Tool, a Dynamic Solutions GIS linkage tool, Dynamic Solutions developed hydrologic runoff models (HEC-HMS) to simulate streamflow hydrographs in the Third Creek and Fourth Creek watersheds. The storm event-driven streamflow results of the hydrologic models were then linked for input to a one-dimensional hydraulic model (HEC-RAS) to simulate the response of water surface elevation profiles to the storm event hydrographs. Using Dynamic Solutions GIS tools (DTM_Tool), simulated water surface profiles were linked with DEM topography to generate GIS maps identifying the areas of the floodplain impacted by the storm events. Animations of the HEC-RAS hydraulic model results were also created by Dynamic Solutions to clearly show overbank flow, inundation and recession of flood waters in the stream channel and floodplain of Third and Fourth Creeks. The findings of the DSI flooding analysis of Third and Fourth Creeks were used by Knox County and the City of Knoxville to support the mitigation of flooding and sedimentation problems in these two watersheds.