Fairfax, Va. — The U.S. Army Corps of Engineers (USACE) Mobile District selected Dewberry to support a flood risk management feasibility study that aims to quantify flood risks and related flooding issues associated with the Sweetwater Creek Watershed in Georgia, and to identify potential projects to reduce flood risks. The Sweetwater Creek basin, located in portions of Cobb, Douglas, and Paulding Counties, Georgia, is approximately 260 square miles and drains southeast, discharging into the Chattahoochee River. This basin has a history of severe flooding, including a historic flood event in September 2009 that caused extensive damage throughout portions of Cobb County.
Dewberry is developing hydrologic and hydraulic models for roughly 75 miles of stream. The models are being developed using the USACE Hydrologic Engineer Center’s (HEC) modeling suite to enable a direct comparison of potential flood mitigation project benefits. A key piece of software being implemented is the HEC’s new Watershed Analysis Tool (HEC-WAT), which provides a framework for integrated modeling and assessment of project alternatives. Historic events, including the July 2005 and September 2009 floods, will be used to calibrate the models and demonstrate the potential project benefits. The firm is analyzing six design alternatives along Sweetwater Creek and its tributaries, including channelization, retention, and diversion structures.