INVESTIGATION OF DRY-WEATHER POLLUTANT ENTRIES INTO STORM-DRAINAGE SYSTEMS

This article describes the results of a series of research tasks to de velop a procedure to investigate non-storm-water (dry-weather) entries into storm-drainage systems (Pitt et al. 1993a, 1993b). Dry-weather f lows discharging from storm-drainage systems contribute significant po llutant loadings to receiving waters, and although they can originate from many sources, the most significant include sanitary wastewater, i ndustrial- and commercial-pollutant entries, failing septic-tank syste ms, and vehicle-maintenance activities. Protocols are discussed to cha racterize the drainage area, locate and identify polluted outfalls, es timate the magnitudes of non-storm-water entries, and locate and corre ct the non-storm-water entries into the storm-drainage system. If thes e loadings are ignored (e.g., by only considering wet-weather storm-wa ter runoff), only limited improvement in receiving-water conditions ma y occur with storm-water pollution-control programs.