Storm Water - SUSMP

• Intent
• Goals
• Guidelines for the Santa Rosa Area
• Implementation
• Boundary

Intent

The Standard Urban Storm Water Mitigation Plan (SUSMP) has been developed as part of the County’s Storm Water Management Program to address post-development storm water pollution and peak flows from new development and redevelopment projects. Implementation of this plan constitutes the managment of storm water to the maximum extent practicable for development and redevelopment projects. Urban development increases storm water volume, velocity and pollutant load. Two important changes can occur during urban development.

First, where no urban development has previously occurred, natural vegetated pervious ground cover may be converted to impervious surfaces such as paved highways, streets, rooftops, and parking lots. Natural vegetated soil can both absorb rainwater and remove pollutants, providing a very effective natural purification process. Because impervious pavement and concrete can neither absorb water nor remove pollutants, the natural purification characteristics of the land are lost.

Secondly, urban development can create new pollution sources as human population density increases and may bring with it higher levels of car emissions, car maintenance wastes, municipal sewage, pesticides, household hazardous wastes, pet wastes, trash, etc., which can be washed into the storm drain system.

As a result of these two changes, the storm water runoff leaving a newly developed urban area may be significantly greater in volume, velocity and/or pollutant load than pre-development storm water runoff from the same area. In addition, the cumulative increase in off-site runoff may cause downstream erosion and flooding, which can subsequently increase sediment loads to the entire storm water conveyance system.

Goals

The SUSMP goals are to manage storm water runoff from new development and redevelopment for both quality and quantity, as close to the point of origin as possible, and to conserve natural areas of the development site.

The first goal is to prevent pollutants generated at developed or redeveloped sites from reaching the storm water conveyance system to the maximum extent practicable.

The second goal is to limit storm water flows from post-development sites to predevelopment quantities to the maximum extent practicable.

The third goal is to conserve natural areas of a development site to the maximum extent practicable.

Guidelines for the Santa Rosa Area

The County of Sonoma and the City of Santa Rosa have produced SUSMP Guidelines. The Guidelines serve the professional design community and municipal staff in implementing SUSMP Best Management Practices on applicable projects.

Implementation

Implementation of SUSMP on applicable projects is effective as of June 27, 2005.

Boundary

The SUSMP boundary includes the City of Santa Rosa and unincorporated areas near the cities of Healdsburg, Windsor, Santa Rosa, Rohnert Park, Cotati, Sebastopol, Petaluma and Sonoma.

Map of SUSMP Boundaries

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