Stormwater discharges continue to cause impairment of our Nation’s waterbodies. Conventional stormwater infrastructure, or gray infrastructure, is largely designed to move stormwater away from urban areas through pipes and conduit. Runoff from these surfaces can overwhelm sewer systems and end up contaminating local waterways. When stormwater runs off impervious streets, parking lots, sidewalks, and rooftops, it can carry pollutants to streams, rivers, and lakes. Runoff flows can also cause erosion and flooding that can damage property, infrastructure, and wildlife habitat. In addition to runoff problems, impervious surfaces also prevent water from penetrating the soil and recharging groundwater supplies.
Green infrastructure, such as rain gardens, and porous pavement, is becoming an increasingly attractive way to reduce the amount of stormwater runoff that flows into wastewater treatment plants or into waterbodies untreated, and to recharge aquifers. It provides many environmental, social, and economic benefits that promote urban livability, such as improved surface water quality, water conservation, and improved aesthetic and property value. EPA researchers have been studying green infrastructure practices and developing models and tools to help communities manage their stormwater runoff and address nutrient impairment.
EPA’s National Stormwater Calculator is a software application that estimates the annual amount of rainwater and frequency of runoff from a specific site. This webinar will introduce the newest features of the Calculator, which is now available as a mobile web application and can be used on smartphones and tablets.
EPA has also added a cost estimation module that allows planners and managers to evaluate green infrastructure practices based on comparison of regional and national project planning level cost estimates and predicted performance.