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