Abstract: Session E  1:30 pm (Back to Session F)
Natural Channel Design and Flood Control – A Bexar County Example

Abigail Bush, PE, CFM, ENV SP
San Antonio River Authority
San Antonio, TX

Mohamed A. Bagha, PE, PMP, CFM
Michael Baker International
Katy, TX

Michael International was contracted by Bexar County Flood Control to remove multiple residential properties from the 1% annual chance (100-year) storm event floodplain and eliminate multiple low water crossings in the Evans Valley Subdivision and at the intersection of Diamond K and Bar X Trail within the city limits of Helotes, Texas. This project is located over the Edward Aquifer Recharge Zone, as well as contained areas of sensitive geologic features and bedrock. This project utilizes natural channel design (NCD) elements, in order to minimize use of concrete riprap and other hard armoring techniques. The purpose for implementing a NCD approach where channel modifications are necessary is to provide a design that is geomorphically stable, minimizes environmental impacts, and to make improvements to French Creek and associated tributaries for the purpose of removing over 50 homes in the Cedar Springs and Evans Valley subdivisions from the floodplain. The flood control effort also included improvements to 6 culverts.