Stormwater one

Stormwater carries polluted runoff from streets, rooftops, parking lots, industrial facilities and construction sites into water bodies. This major source of pollution has attracted much more attention lately, and controlling stormwater pollution is critical to improving and maintaining water quality in the most populated areas and rapidly developing areas of the country.

The 1987 Amendments to the Clean Water Act set the process of controlling stormwater pollution into motion. The changes were developed and instituted in two phases. In the early 1990s, “Phase I” required cities with populations over 100,000, industrial facilities, and construction sites five acres or greater in size to obtain a NPDES permit. These regulations, which depended primarily on stormwater management plans, have driven major urban stormwater control programs in the largest cities during the past decade.

In March of 2003, “Phase II” regulations kicked in, which required all communities within “urbanized areas” with at least 50,000 people to apply for a NPDES stormwater permit. “Urbanized areas” were determined by population and density (based on the 2000 census), and they include some communities that are much smaller than 50,000 people. In addition, Phase II requires permits for any construction activity that disturbs one acre or greater, and it has significantly expanded the number of industrial categories that can claim exemption from stormwater regulations.

The EPA has set some minimum federal requirements for all municipal, industrial and construction stormwater pollution permits and programs. However, these requirements do not include technology- based effluent limits similar to those that are in municipal and industrial wastewater discharge permits. Instead, they rely a) on stormwater management plans to identify best management practices that will reduce stormwater pollution AND b) full implementation and monitoring of those practices. Without specific, required limits, state permits vary widely across the country. States may impose stricter rules and tighter timetables for compliance, and some states have.

Stormwater permits are required for two major categories of stormwater pollution: municipal and industrial. Within each category are several distinctions. Municipal stormwater permits are broken down by population. Large and medium cities were required to manage their stormwater in the early to mid-1990s. In March 2003, smaller urbanized areas were incorporated into the stormwater program. Industrial activity is broken down into eleven categories. Construction activity is one of those categories. It warrants particular attention because separate NPDES permits are required for construction sites one acre or greater to control erosion and sedimentation.