The amount of impervious surfaces – roads, parking lots, driveways, sidewalks, patios, and rooftops – increases as land is developed. As naturally pervious areas are replaced by impervious surfaces, a greater percentage of rainfall flows off the land as stormwater runoff instead of infiltrating into the ground. The increased volume and velocity of runoff flowing off of impervious surfaces may harm natural resources. Stormwater runoff also picks up pollutants – including car oil, fertilizers, pesticides, sediment, pet waste, and trash – and carries these pollutants to waterways and the ocean.

Low Impact Development (LID) is an approach to stormwater management that aims to replicate the site’s natural hydrologic balance. LID emphasizes site design strategies that protect the site’s natural capacity to retain stormwater, integrated with small-scale distributed Best Management Practices (BMPs) that rely on on-site infiltration, evapotranspiration, harvesting, detention, or retention of stormwater runoff. Coastal Commission Water Quality Program staff recommends giving precedence to an LID approach to stormwater management in all development.

Examples of LID site design strategies include minimizing impervious surface area, preserving natural vegetation, conservation and use of natural drainage features, maintaining the infiltration capacity of the soil, and directing runoff from impervious surfaces into pervious areas. Examples of LID BMPs include rain gardens, grassy swales, permeable pavements, rain barrels, green roofs, soil amendments, planting native plants, and bioretention systems.

Low Impact Development workshop materials

  • Low Impact Development Workshops

    The Coastal Commission's Water Quality Program coordinated four LID workshops that were held along the California Coast in April 2008. See the presentation slides, handouts, and other useful materials from each of the workshops.

Additional resources on Low Impact Development

  • California LID Portal

    This website provides links and references to Low Impact Development material available from many sources, as well as information and tools specifically developed by the California Stormwater Quality Association (CASQA) and partner organizations to support the California stormwater management community.
  • LID Urban Design Tools

    Website, by the Low Impact Development Center. Design tools (including specifications, sizing, construction schedule, costs, maintenance, benefits, and examples) for bioretention, green roofs, permeable pavers, rain barrels & cisterns, soil amendments, and tree box filters.
  • Low Impact Development (LID) "Barrier Busters" Factsheet Series, by U.S. EPA

    This factsheet series is primarily intended for state and local decision makers who are considering adoption of an LID approach to stormwater management.