Keep It Local: Sustainable Storm-Water Management Methods on Urban Streets

Abstract

Los Angeles County Department of Public Works' Brandon and Green Streets Project started out as a traditional road improvement project to construct missing roadway, sidewalk, and curb improvements on an urban residential street to match the surrounding street improvements. An underground storm drain lateral extension was also planned. One of the Public Works' Strategic Focus Areas is to invest in sustainability, and the emphasis on storm-water capture is being shifted to ground infiltration and away from storm drain conveyance. Located in the unincorporated area of East Pasadena, this $2 million project was designed to demonstrate the effectiveness of sustainable features that would reduce flows into the existing storm drain system so that the new storm drain extension could be eliminated. The sustainability features would improve the water quality of remaining runoff into the existing storm drain. Parkway bio-retention planters were designed for installation between the curbs and the sidewalks with curb inlets and outlets to infiltrate and filter runoff. The bio-retention planters will be landscaped with trees and drought-tolerant native plants. Sidewalks and street gutters were designed to incorporate porous concrete for infiltration on a portion of the project. Permeable pavers will be installed in cross-walk areas and in place of roadway pavement at the end of a cul-de-sac to further enhance ground infiltration. Sediment catch basins and an underground infiltration basin will be installed at the cul-de-sac. A monitoring program will be implemented at the bio-retention planters and at the sediment filtration catch basin to evaluate water quality effectiveness. The project team worked with residents, utility companies, and other stakeholders to overcome design challenges and to make the proposed improvements effective, aesthetic, and meet engineering criteria such as Americans with Disabilities Act (ADA) compliance standards. In community meetings, the residents were pleased with the sustainable elements and agreed to partner in the maintenance of the bio-retention planter landscaping.