CP&Y prepared a preliminary engineering report (PER) for this flood control project which was part of the Bexar County Flood Control Division Bond Program. CP&Y also performed detailed design and PS&E. The scope of the project was to provide un-flooded access on this City of San Antonio classified secondary arterial. This section of roadway overtopped by up to 3.75-feet of water during a 100-year storm event. Improvements included the replacement of three culvert crossings within the project limits with three cast-in-place (CIP) slab span bridges. The roadway section was widened from a 2-lane to a 4-lane roadway with curbs and sidewalk.
The project also included extensive channel excavation both upstream and downstream of the roadway that required coordination with U.S. Army Corps of Engineers (USACE), U.S. Fish and Wildlife Service, and the Texas Commission for Environmental Quality. The roadway profile also had to be raised three feet, which was accomplished by a geotechnical investigation, analysis of the existing drainage conditions and site investigations.
During detailed design, natural channel design elements were implemented in the flood control portion of the project. These elements included meandering low flow channels, pool/riffle sequences, and in-channel depressions to enhance aquatic habitat. The loss of trees was mitigated by broad replanting efforts. An adjacent detention pond for a subdivision was repurposed as a water quality pond to treat runoff from the new roadway surface. This proposed sand filter sedimentation/filtration pond also provides additional capacity for future roadway development along the Hausman Road Corridor. The buyout and subsequent removal of flood-prone structures resulted in an overall reduction of impervious cover for the project, providing additional water quality benefits to the watershed. USACE NWP 27 was applicable to the proposed work and received no review comments. Final permitting also included a CLOMR for FEMA and a Stormwater Management Plan for the City of San Antonio.
Update of dFIRM Hydraulic Models
Roadway and Bridge Design
Extensive Channel Excavation Design
Development of Baseline Qualitative Habitat Indices
Tree Diameter Surveys
Natural Channel Design Implementation and Aquatic Resource Enhancements
Mitigation Plan Preparation and USACE NWP 27
San Antonio, Texas
46 Acres for Channel Improvements
and Aquatic Features