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Low Impact Development (LID)

The West Placer Post Construction Stormwater Design Manual is a joint effort between Placer County and the Cities of Roseville, Lincoln, Loomis, and Auburn. The goal of the Design Manual is to provide standards that both conform to the mandates of the 2013 NPDES Municipal Permit (MS4-General Permit No. CAS0000004) and achieve the objectives of the Placer County Conservation Plan (PCCP).

The West and East Placer Storm Water Quality Design Manuals are available for download here.


The County is also developing an Aquatic Resource Program (CARP) that will streamline permitting processes within a stream system. Low impact development is critical for PCCP/CARP implementation to ensure Clean Water Act permit requirements are satisfied.

The Design Manual will provide hydromodification management to satisfy requirements for stormwater discharges as part of the Small Municipal Separate Storm Sewer Systems (MS4), Phase II of the National Pollution Discharge Elimination System (NPDES) small municipal stormwater program. This program, which is part of the Federal Clean Water Act, requires the County to regulate all projects that create and/or replace 5,000 square feet of impervious surface.

Frequently Asked Questions

Q: What is LID?

A: LID, or low-impact development, refers to an approach to stormwater management that improves water quality by reducing the amount of pollution from stormwater that enters our creeks and rivers. Impervious surfaces like parking lots and buildings impair our streams by increasing the amount of stormwater runoff that enters waterways. This runoff includes car oil, litter, gasoline, and other contaminants. The increased runoff further impairs waterways by contributing to erosion, stream incision, and sedimentation. Water quality and habitat for aquatic life is ultimately compromised. The term used to describe how development increases runoff is called “hydromodification.” By ensuring future development is constructed in a manner that reduces these impacts, water quality can be improved.

Q: What are some examples of LID practices?

A: Green roofs, permeable pavement, rain gardens, bio-retention swells, reducing and disconnecting impervious surfaces are all examples of LID practices.

Q: How is LID good for my community?

A: LID has multiple benefits for municipalities, developers, property owners, and the environment. LID improves water and air quality, encourages groundwater recharge, reduces stormwater management, and balances growth needs with environmental protection.

Rain gardens capture stormwater and allow for infiltration   Rain gardens capture stormwater and allow for infiltration

Green roofs absorb stormwater and provide additional insulation   Green roofs absorb stormwater and provide additional insulation

Vegetated basin at Northstar is a great local example of LID   Vegetated basin at Northstar is a great local example of LID

Local Watershed Groups

Save Auburn Ravine Salmon and Steelhead

Dry Creek Conservancy

Friends of the River

American River Conservancy

North Fork American River Alliance

Protect American River Canyons

Save the American River Association

Foothills Water Network

Placer County Stormwater Quality Program

For more information on the West Placer LID Manual, contact: