The Runoff Reduction Method



The Runoff Reduction Method (RRM) provides an innovative approach to crediting the total performance of stormwater best management practices (BMPs). Total BMP performance refers to the pollutant removal and runoff volume reduction capabilities. The RRM tracks the implementation of stormwater BMPs, including Low Impact Development (LID) strategies such as permeable pavement, rainwater harvesting, downspout disconnection, soil amendments, etc., and credits the appropriate runoff volume reduction, pollutant concentration reduction, or both towards compliance with stormwater quality and quantity requirements. By providing a mechanism to credit the volume reduction associated with these LID strategies the RRM also documents an allowable reduction of the overall size and footprint of structural detention practices, thereby providing an economic incentive for the development community to implement LID providing a better overall solution for minimizing the impact of development on the hydrologic cycle.