Small Alley Retrofits Equal Big Benefits for Storm Water Management
Urban alleys are often underutilized and are commonly associated with undesirable activities. More recently, we are recognizing their potential to provide stormwater management opportunities in high-density urban areas. Retrofitting parcel-scale sites with LID BMPs to capture and treat urban run-off results in large-scale water quality benefits. The Elmer Paseo Stormwater Improvement Project is one of the first neighborhood alley retrofit projects in Los Angeles to achieve both stormwater management goals and provide additional benefits to the community.
The Elmer Paseo features a bio-swale, a pervious concrete pathway, an infiltration trench, and a palette of native plants. The alley reduces flooding, has the capacity to infiltrate 6 acre-feet of runoff annually, filters and cleans polluted runoff, provides habitat for native birds and insects, and creates needed green space for the neighborhood. Since 2013, the Council for Watershed Health has implemented a comprehensive monitoring program to assess the performance of this small-scale alley to capture and treat stormwater and to provide additional benefits.
This presentation will describe how the Council transformed a degraded asphalt alley into a community green space that optimizes stormwater capture, treatment and infiltration. The monitoring results-to-date demonstrate the water quality and supply benefits and as well as additional benefits of these alleys for the surrounding neighborhood.