Avalon Green Alley Network: Low Impact Development (LID) Demonstration Project in Los Angeles, California

Stormwater poses flooding and pollution hazards in urban areas. The impacts of polluted urban stormwater have given rise to low impact development (LID). The Avalon Green Alley Network: LID Demonstration project is a joint partnership between the City of Los Angeles Bureau of Sanitation, the trust for public land, the council for watershed health, the coalition for responsible community development, and the Los Angeles Conservation corps to develop LID design interventions for stormwater infiltration in South Los Angeles. The project is located in public alleys right-of-way in high-density neighborhood blocks. The alley is bordered primarily by residential units and is adjacent to a schools, parks, and commercial building with parking lot. The project slows, infiltrates, and retains stormwater on site, capturing runoff from the intersecting streets catch basin intercepts, using dry well chambers, replacing asphalt with permeable surfaces, percolating stormwater, and providing underground storage. Runoff drains toward interlocking pavers to allow stormwater to flow into an underground infiltration trench for treatment. Overflow from these trenches then flows to a dry-wells system where it infiltrates into the ground. Water quality monitoring includes groundwater motoring wells, flow meters, and series of level-loggers have been installed in the alley to quantify water quality and water-supply benefits. In addition to water quality components, the project has other benefits for the community, including the growing of vines and espalier trees, artistic paving, and artwork in the form of poetry.