Location: One pond at each quadrant of I-35 and Ben White
Pond Watershed: 29 acres for four ponds
Impervious Cover/Drainage Area: 85%
Pond Goal: Water Quality Protection
Pollutant Removal: 23,000 lbs. of total suspended solids (TSS) removed annually
This project was initiated at the request of an Austin Transportation Study Water Quality Task Force as a response to citizen concerns regarding the TxDOT tunnel being built under IH35 to capture runoff from the Ben White/IH35 expansion. Citizen concerns focused on the lack of treatment and potential for pollutant runoff prior to discharge into Williamson Creek. Four sedimentation/filtration basins, one at each corner of the Ben White/IH35 intersection have been constructed to treat approximately 29 acres of primarily highway runoff. A bioretention pond will be constructed for treatment of the small storm runoff and will be located upstream of where the tunnel outfalls into the creek. This mitigation plan was approved and the Austin Transportation Study Policy Advisory Board authorized STP 4C funds to match the City's contribution to the project.