Bioretention basins are a type of treatment control Best Management Practice (BMP) designed to reduce stormwater pollution through natural processes. These basins use a combination of vegetation, rocks, and soil media to capture, filter, and biologically degrade pollutants found in stormwater runoff. By slowing the flow of stormwater and allowing it to soak into the ground, bioretention basins help reduce runoff volume and improve infiltration. Additionally, they are effective at filtering out micro-pollutants and bacteria, supporting cleaner downstream waterways.

​When designing or proposing a bioretention area, our student leaders consider the size and capacity of the site to ensure it can effectively manage and treat anticipated stormwater volumes.

​At San Clemente High School, our Stormwater Quality Leadership interns identified storm drains on campus that were impacted by high levels of coliform bacteria. In response, the students proposed the installation of a bioretention basin to capture and naturally treat stormwater from these areas. After assessing the campus layout, they determined that the school had suitable space to support a dedicated biofiltration system. Their plan not only addressed a key water quality concern but also demonstrated a scalable and sustainable solution for long-term stormwater treatment.