Protecting the Edwards Aquifer with StormTech and BayFilter

To safeguard the Edwards Aquifer in Texas, the developer of the Natural Grocers store in Georgetown, Texas chose to employ two storm water management systems to provide enhanced filtration and debris trapping. This site is a part of the 1,100-acre Wolf Ranch planned community, which includes 2,400 single-family homes and 900 multifamily units.

The Edwards Aquifer is a large underground water source that covers approximately 4,350 square miles of south-central Texas, including the cities of San Antonio and Austin. It is the main source of drinking water for nearly two million people and provides water for agriculture and industry in the region. The aquifer's karst hydrogeology makes it susceptible to contamination from chemicals and debris that can quickly spread through the system. Aquifers in general are vulnerable to pollution when pollutants enter the recharge zone.

“Initially, our engineers looked at options including an open pond, along with a sand filtration system and standard large concrete detention basin underneath,” explained Kevin Beck, development manager for Equity Ventures Commercial Development (Topeka, KS). “Within the state of Texas and especially in and around Austin, there’s significant sensitivity to the environmental areas,” he continued. “This aquifer is of particular importance to the state and to the region, and therefore to protect it and still allow development, we wanted to go with the higher removal rates to be very protective of that aquifer.”

The stormwater management system consists of two units that are designed to handle a 100-year storm and have a capacity of nearly 17,000 gallons of water. This includes a detention system with 198 StormTech SC-740 chambers and a StormTech Isolator Row. Water flows into the system from a grate in the parking lot, where it is first treated by the Isolator Row to trap sediments and other contaminants. The water then passes through the BayFilter Model 522, which has six removable filters for additional treatment. The treated water is then discharged into the San Gabriel River. The BayFilter system is designed to remove fine sediments using spiral wound media filters and has been approved by the Texas Commission on Environmental Quality for unrestricted use over the Edwards Aquifer. It meets the Edwards Aquifer Rules Technical Guidance on Best Management Practices RG-348.

“Because this project is above the Edwards Aquifer that is the reason why we used the two StormTech systems we did,” Beck explained. “There are stringent guidelines regarding pollutant removal from stormwater runoff in this area, which we exceeded, removing 87 percent of the particulates including oils, fuels, dirt and sand plus debris.”