Phase II BMP & Measurable Goal Examples
POST-CONSTRUCTION STORM WATER MANAGEMENT IN NEW DEVELOPMENT/REDEVELOPMENT MINIMUM MEASURE
New development and significant redevelopment projects offer a host of opportunities to install structural runoff controls on both the site and regional scales.
Hypothetical Case Study: Smalltown, USA, has substantial existing development and many neighborhoods that are still growing. For existing development, the City plans to use on-lot treatment to handle some storm water by disconnecting impervious surfaces. The City also wants to ensure that existing storm water controls are functioning properly. Growing areas will also be targeted by requiring impervious area disconnection and new storm water controls.
Minimum Measure Objective: Reduce the volume and improve the quality of storm water runoff by disconnecting impervious surfaces and installing and maintaining structural storm water controls.
BMP: Reduce directly connected impervious surfaces in new developments and redevelopment projects by requiring that grassed swales or filter strips be installed along roadsides in lieu of curbs and gutters
Measurable Goal: Directly connected impervious road surfaces in new developments and redevelopment areas will be reduced by 30 percent (relative to the traditional scenario in which curbs and gutters are used) over the course of the first permit term.
Justification: Opportunities abound to provide treatment and infiltration of runoff in the right-of-way adjacent to roads. This practice would provide on-lot treatment of storm water, reduce the total volume of storm water being discharged from sites, and increase the time of concentration of the runoff that is generated from road surfaces.
BMP: Develop a program for maintenance of structural storm water controls
Measurable Goals: In the first year, conduct an inventory of structural runoff controls. In year 2, develop a GIS to integrate the location of these controls with schedules for regular inspection and maintenance. Conduct four inspections of each structural control per year and conduct regular maintenance as prescribed for each type of practice.
Justification: There are many structural controls located throughout the municipality that are owned and operated by both public and private entities. Before a comprehensive maintenance plan can be implemented to address all of the practices, a complete list of BMPs and their locations and site conditions needs to be compiled. An inspection and maintenance schedule can be developed to maximize efficiency and minimize labor requirements. The system can be expanded to include other types of MS4 maintenance, including street sweeping, catch basin cleaning, storm drain flushing, etc.
BMP: Develop and implement a storm water ordinance and guidance or a design manual that include performance standards designed to control runoff impacts
Measurable Goal: By year 3 of the permit term, 95% of all building permits will include descriptions and plans regarding storm water control practices and site designs that comply with the criteria and guidance specified or referenced in the municipal code.
Justification: Ordinances are an effective way to establish performance standards for runoff controls. These performance standards might, for example, specify a target for percent removal of annual post-development total suspended solids loadings, require maintenance of annual ground water recharge rates, or limit runoff volumes and rates such that receiving waters are not negatively impacted.
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