Possible Points: 20 points.
Learn from the experiences of a community that was successful in earning credit for this CRS element! Check out the Success Story for Bristol, RI.
Purpose of Element: Implementation of permanent practices that help to improve the quality of stormwater can help to enhance the quality of degraded waterways and protect those that are still pristine. The purpose of this element is to reward communities for requiring developers to install permanent, stormwater best management practices (BMPs). These best management practices could include techniques like implementing filter strips, retention pond such that sediments are encouraged to settle out of the water column, and bioswales. Many states have specific guidance available regarding appropriate stormwater best management practices. For more information reference pages 450-20 450-22 of the CRS Coordinator’s Manual.
Impact Adjustment: None.
Potential to Double Count Credit: None.
Degree of Difficulty - Documentation: Low. The documentation requirements for this element are minimal. The only thing that communities must put together are a copy of the community’s relevant ordinance and copies of building permits that can be used to verify that the community’s ordinance is being enforced.
Degree of Difficulty - Implementation: Low. The implementation of permanent BMPs after the construction of new development is one of the requirements of the National Pollution Discharge Elimination System (NPDES) permit for most communities. Specifically, in communities with a Municipal Separate Storm Sewer System (MS4) permit, all development that disturbs one or more acres of land must have post construction BMPs implemented on-site in order to mitigate the additional stormwater runoff caused by the new development (EPA, no date). As a result, most communities should already have regulations of this nature implemented, and can simply fulfill the documentation requirements outlined for this element in order to receive CRS credit.
That said, very small, rural communities that do not have a MS4 permit may need to implement a new regulation in order to earn credit for this element. This is because some development that is one acre or more in size is subject to the EPA’s Construction General Permit. While this permit requires developers to implement post-construction BMPs, it does not require this standard to be formally adopted into the community’s code of ordinances (EPA, 2007; US EPA, 2017). The integration of this requirement into the community’s ordinances and ultimately its enforcement is required in order to take credit for this element under the CRS program.
Tips for Success:
- Many states have issued guidance on stormwater management BMPs. This may come in the form of a reference document, design manual, guidebook, etc. Two example are the Minnesota Pollution Control Agency’s Stormwater Best Management Practices Manual and Rhode Island's Stormwater Design and Installation Standards Manual.
- The Center for Watershed Protection has created a model ordinance and self-assessment tool for post-construction stormwater management programs. Communities that do not have applicable ordinances in place can use this document as a reference.
Co-Benefits Associated with this Element: Best Management Practices (BMPs) help to manage stormwater in two ways. First of all, green infrastructure practices such as infiltration basins, rain gardens, and bioswales are designed to manage excess water by capturing it where it falls, thereby allowing it to infiltrate into the soil and reducing the total volume of stormwater runoff. Reducing the total volume of stormwater runoff can help to reduce localized flooding, especially in large urban areas where stormwater infrastructure is sometimes under designed for the current needs of the city. Second, the use of green infrastructure is also associated with a reduction in pollutant loading because these systems typically work by either slowing water down and spreading it out or by capturing water and allowing it to be absorbed naturally. In doing this, sediments and other contaminants are provided with the opportunity to settle out of the water column, thereby reducing the quantity of pollutants that reach waterways. Specifically, a survey of the published literature on the efficacy of green infrastructure showed that BMPs are associated with 15-58% reduction in Total Nitrogen, a 58-80% reduction in Total Suspended Solids, a 52-70% reduction in peak flow rates and a 57-85% reduction in runoff volumes depending on the practice implemented (Jaffe et al., 2010).