Improving Post-Construction Stormwater Management Program Results through Incorporation of Performance Verification Standards for Stormwater Control Measures

There are a wide variety of post-construction stormwater management systems available for use in the United States that are intended to mitigate the water quality and hydrologic impacts of urban development. Conventional systems like bioretention, ponds, swales and infiltration trenches have been studied for decades and appear in most stormwater permits or implementation manuals, acceptable as either stand-alone or pretreatment practices. There are also over fifty innovative, often proprietary stormwater management systems currently available that improve on some aspect of conventional public domain systems. In response to an identified need for reliable and comparable performance information for all stormwater control measures (SCMs), the Stormwater Testing and Evaluation of Products and Practices (STEPP) program was initiated and is making progress toward establishing a national testing and verification process. The STEPP program draws heavily on the success of two state level performance verification and certification programs, the Technology Assessment Protocol – Ecology (TAPE) program from the Washington State Department of Ecology and the Filter and Hydrodynamic separator laboratory testing protocols from the New Jersey Department of Environmental Protection (NJDEP). Both programs are already widely referenced outside of their respective state boundaries in stormwater permits and stormwater management manuals. By recognizing performance verification reports and certification statements from these programs, other agencies can avoid the cost, complexity and potential liability of developing their own unique SCM verification programs. This paper identifies more than 20 different references to the TAPE and NJ DEP or NJ CAT programs by jurisdictions outside of Washington and New Jersey and identifies examples of language that can be adopted by other programs seeking to improve the reliability of their stormwater management infrastructure.