Benefits of Compact, Mixed Use Development

This report from the EPA outlines the effects development has on watersheds and examines the differences in impacts stemming from urban form. It estimates impacts from three different development scenarios. Runoff impacts were estimated using the Smart Growth Water Assessment Tool for Estimating Runoff which uses event mean concentrations, daily rainfall, and curve numbers from the National Resources Conservation Service. Development scenarios only took into account new, non-infill residential development, which was assumed to be single-family. The three development scenarios were one, four, or eight houses per acre with each having a square footage of 2,265 square feet. The report concludes that increases in density increase the amount of runoff per acre, but decrease runoff per house.