The Broad Beach Road Biofiltration Project aims to prevent dry weather flows, and treat feasible volumes of wet-weather flows that might otherwise discharge to the Area of Special Biological Significance (ASBS). The project diverts dry-weather and stormwater runoff from nine storm drain inlets along a one-mile stretch of Broad Beach Road into a combined porous parking and engineered biofiltration system on the north shoulder. Runoff is treated through evapotranspiration and biofiltration.
The preliminary project design report determined that biofiltration would be the most effective means of meeting the project goals, so a system of bioswales, lined to prevent infiltration into the subsoil was installed to filter the stormwater.
The project was accepted as complete by the City Council in August 2015.
Project benefits may include habitat restoration of some of the slopes above Broad Beach Road adjacent to Pacific Coast Highway. Drip irrigation will be utilized to establish the planted vegetation and to maintain their appearance during summer months and extended dry weather. If feasible, water supply for drip irrigation will be drawn from shallow groundwater wells along the biofiltration system, effectively recycling the filtrated rainwater, enhancing evapotranspiration of the system while, at the same time, conserving water and minimizing groundwater mounding.
The project is funded primarily by a $2.25 million grant from the State Water Resources Control Board with contributions from the City.
Project Site Map - Map showing the location of the Broad Beach Biofiltration Project