Low Impact Development [presenters name] [presentation date] Integrated Management Practices Controlling Stormwater Quality and Quantity using

Outline Why do we need to control stormwater quality & quantity? Low Impact Development Integrated Management Practices ●What are they? ●Why use them? How does this affect development project review?

Controlling Stormwater Quality Urban runoff is the main source of pollutants to streams and the Bay. Regional Water Quality Control Board “C.3” permit provisions require [City/Town] to make stormwater treatment a condition of approval.

Increased runoff from impervious surfaces can accelerate stream erosion. “C.3” requires [City/Town] to limit runoff from new developments to pre- project flows and durations, where increased runoff could accelerate stream erosion. Controlling Peak Flows & Durations

These projects must comply ThresholdRequirementDate* One acre or more (impervious area created or replaced) Treat runoff2/15/05 Control peak flows & durations 10/12/06 10,000 square feet or more Treat runoff8/15/06 *development applications deemed complete after this date

Low Impact Development Design the site to mimic natural drainage. Disperse runoff to landscape where possible. Use Integrated Management Practices distributed around the site.

Example of an engineered Integrated Management Practice “Dry” swale detains and filters runoff

Fitting IMPs into landscaping Portland, OregonAlbany, California

Fitting IMPs into landscaping Seattle, Washington Spokane, Washington

Planter Box

Integrated Management Practices Detain and treat runoff Typically fit into setbacks and landscaped areas Accommodate diverse plant palettes Low-maintenance Don’t breed mosquitoes Can be attractive Soil surface must be 6-12" lower than surrounding pavement Require 3-4 feet of vertical “head” Can affect decisions about placement of buildings, roadways, and parking AdvantagesChallenges

Development Review IMPs can be effective, attractive, and accepted by developers Incorporate IMPs in preliminary site, landscaping and drainage design drawings In-ground planter boxes under construction Residential subdivision Clayton, May 2006

Maintenance of IMPs Prior to planning & zoning approval ●Identify maintenance requirements ●Identify maintenance responsibility Typical maintenance requirements ●Check inlets and outlets ●Irrigate and maintain plantings [City/Town] must either ●Accept maintenance responsibility or ●Legally assign it to property owner(s) [City/Town] reports inspection results to Water Board annually

Implementation [City/town] ordinance requires a design exhibit and a report with planning and zoning application Contra Costa Clean Water Program Stormwater C.3 Guidebook explains how to prepare the submittal Staff works with applicant to integrate IMPs into the project