It seems we’ve had a lot more rainfall than usual in Maryland, Virginia and Washington, DC over the past few weeks, so if you haven’t spent any time thinking about your company’s stormwater management plan, this is probably a good time to do so. Stormwater, as the name suggests, is runoff from heavy rainfall and melting snow that doesn’t seep into the ground. As it flows across the ground, it accumulates all sorts of contaminants, such as debris, chemicals and sediment. If left untreated, pollutants carried by stormwater can seriously affect water quality.
Who needs to worry about stormwater management?
The EPA lays out specific stormwater management guidelines for three main sources: municipal storm sewer systems, construction activities and industrial facilities. Specifics pertaining to stormwater management regulations are laid out by the National Pollutant Discharge Elimination System (NPDES).
Stormwater management for municipalities – polluted stormwater is usually untreated when it is sent through Municipal Separate Storm Sewer Systems (MS4s) into local bodies of water. In order to prevent harmful pollutants from being washed or dumped into an MS4, operators must obtain a NPDES permit and develop a stormwater management program. MS4s can be broken into two categories:
- Phase I requires medium and large cities with populations over 100,000 to obtain NPDES permit coverage for their stormwater discharges.
- Phase II requires small urbanized areas with MS4s to obtain NPDES permits to cover their stormwater discharges.
In general, Phase I stormwater management permits are individual and Phase II are more general. Each regulated MS4 is required to have a stormwater management plan that reduces the contamination of stormwater runoff and prohibits illicit discharges.
Stormwater management for construction sites – even more than municipal sewer systems, stormwater runoff from construction sites can have significant impacts on local water quality. When stormwater flows across a construction site it can pick up numerous pollutants, including sediment, debris and chemicals and bring these to a nearby MS4 or directly into a body of water such as a river or lake. Sometimes this stormwater runoff can be so polluted that it can kill fish, birds and other wildlife, destroy aquatic habitats and cause stream bank erosion. Debris can clog waterways and over time can reach the ocean, killing marine wildlife and destroying habitats there too.
NPDES stormwater management programs require construction site operators who are involved in clearing, grading and excavating areas of one acre or more to obtain a permit for stormwater management.
Stormwater management for industrial facilities – since many of the activities that take place at industrial facilities are exposed to the elements, stormwater runoff that flows through industrial sites can collect pollutants and drop them off in a nearby MS4 or directly into a body of water. The NPDES program includes an industrial stormwater permit section that covers 10 categories of industrial activity. These categories are:
- Facilities subject to federal stormwater effluent discharge standards in 40 CFR Parts 405-471
- Heavy manufacturing (for example, paper mills, chemical plants, petroleum refineries, and steel mills and foundries)
- Coal and mineral mining and oil and gas exploration and processing
- Hazardous waste treatment, storage or disposal facilities
- Landfills, land application sites, and open dumps with industrial wastes
- Metal scrapyards, salvage yards, automobile junkyards and battery reclaimers
- Steam electric power generating plants
- Transportation facilities that have vehicle maintenance, equipment cleaning or airport deicing operations
- Treatment works treating domestic sewage with a design flow of 1 million gallons a day or more
- Light manufacturing (for example, food processing, printing and publishing, electronic and other electrical equipment manufacturing, and public warehousing and storage).
If you are trying to get an NPDES permit and need help designing a stormwater management plan for your Maryland, Virginia or Washington, DC municipality, construction site or industrial facility, call the experts at Magnolia Plumbing today. We have decades of experience helping companies throughout the area design effective DC stormwater management plans that minimize the effects of stormwater runoff on the environment.