Rainwater Collection and Management from Roofs at the Edison Environmental Center

Abstract

In the past, the U.S. Environmental Protection Agency Edison Environmental Center, a 80.9-ha (200-acre) federal-run facility, directed all rainwater from roofed areas to the existing storm water conveyance system. Over the last several years, modifications have been made to the practice of discharging storm water to the existing conveyance system due to federal mandates. Roof runoff from approximately 0.28 ha (0.69 acre) has been directed to bioinfiltration units to infiltrate into the ground, while rainfall from another 0.14 ha (0.34 acre) is being captured and used for nonpotable purposes. This paper discusses the water quality of the roof runoff directed to the bioinfiltration units and the reductions in usage of potable water due to a rainwater capture system. The mean pollution concentrations of the roof runoff were for the most part below drinking water standard levels. An exception was antimony because mean concentrations were over the drinking water standards; the primary source of contamination appears to be atmospheric because rainwater correlated with observed roof runoff. On the other hand, copper and zinc in the roof runoff was higher than rainfall concentrations due to exposure to metal components on the roof. Approximately