This fall, the U.S. Environmental Protection Agency will release the National Stormwater Calculator. It is a tool designed to help city planners, developers, and property owners assess the runoff-reduction benefits of green infrastructure on specific sites.

Taking into account local soil conditions, land cover, and historical rainfall records, the calculator will determine the annual amount and frequency of stormwater runoff from locations anywhere in the U.S. The tool can examine how stormwater runoff changes under different development and green infrastructure scenarios.