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Low Impact Development (LID)

Low Impact Development, or LID, is a design strategy using naturalistic, on-site Best Management Practices to lessen the impacts of development on stormwater quality and quantity. The goal of LID is to mimic the undeveloped runoff conditions of the development site with the post-development conditions. As of Jan. 1, 2009, the County of Los Angeles instituted LID requirements for development occurring within unincorporated portions of the County. The following documents are available for download:


LID Manual
The LID Manual explains how a site designer/engineer could use a wide array of simple cost-effective techniques that focus on site-level hydrologic control to meet Low Impact Development regulations. The LID manual describes those techniques, provides examples and descriptions of how they work, and contains BMP fact sheets.  View


LID Calculator
The LID Calculator allows the site designer/engineer to calculate runoff rates and volumes from the water quality storm.  Download