An Overview of EPA's NPDES Construction Stormwater Permitting Program

The National Pollutant Discharge Elimination System (NPDES) permit program regulates the discharge of pollutants to waters of the United States. NPDES permits have traditionally been issued to industrial and publicly owned wastewater treatment plants; however, 1987 amendments to the federal Clean Water Act added stormwater to the NPDES permitting universe. EPA issued regulations in 1990 requiring NPDES permits for stormwater discharges from large municipalities and certain industrial sources (including construction sites disturbing at least 5 ac.). Permits from these sources were required to be submitted beginning in 1992. EPA issued new regulations in 1999 to require NPDES stormwater permits from smaller cities and smaller construction sites.

Most states have been delegated authority to run the NPDES permitting program and issue NPDES stormwater permits within their state boundaries. EPA regional offices still issue NPDES stormwater permits in nine states/territories (AK, AZ, DC, ID, MA, ME, NH, NM, and PR) and on federal facilities or Native American lands in some delegated states.

What does all this mean for construction operators? You're currently required to obtain an NPDES construction stormwater permit if your site disturbs at least 5 ac. Beginning around March 2003, you will need an NPDES permit if your site disturbs at least 1 ac. These permits are in addition to any other erosion and sediment control requirements placed on you by state or local governments.

Construction Disturbing More Than 5 Acres

The SWPPP is basically an erosion and sediment control plan. It is up to the construction operator to decide what types of best management practices (BMPs) to use on-site, but he or she must comply with the permit requirement, which describes the contents of the SWPPP. The plan requires a site description, including a map; a description of sediment and erosion controls used on-site, including stabilization practices (e.g., seeding, mulching) and structural practices (sediment traps, silt fences); a description of BMPs to control stormwater runoff after completion of the construction project; and BMPs to control solid material and other construction waste. In addition, maintenance and inspection practices must be described.

Construction Disturbing Less Than 5 Acres

Although these small construction permits will not be issued until late in 2002, EPA stated that the requirements will be very similar to the requirements placed on large construction sites. There are a couple of key differences between large and small construction sites. The first major difference is that, unlike large construction sites disturbing more than 5 ac., small construction sites can be waived from the NPDES permitting program based on either the rainfall intensity anticipated for the project period (the "R" factor from the Revised Universal Soil Loss Equation) or a water-quality analysis that shows construction controls are not necessary to protect water quality. It is up to the permitting authority whether or not to use these waivers, and several states are contemplating not allowing any waivers because of the low number of sites that would qualify for the waiver.

The second major difference is that EPA is not specifically requiring permitting authorities to collect NOIs from small construction sites. These NOIs are used to track sites and prioritize inspections, so EPA says it strongly recommends their use. If a state chose not to require NOIs, however, small construction sites in that state would still need to develop and implement an SWPPP, but would not have to submit any paperwork. The drawbacks associated with not requiring an NOI (difficulty in finding sites for inspections, no permit fees collected) might push most states to require NOIs from small construction sites.

Other minor changes made by the new construction regulations include a specific exemption from permitting requirements for routine maintenance performed on small sites (such as regrading dirt roads; and the ability of both large and small construction permits to require permittees to follow the state erosion and sediment control program; instead of preparing a duplicate plan for the NPDES permit. The construction site would still need to apply for an NPDES permit, but the permit would not require the construction operator to duplicate any work already completed to comply with state (or local) erosion and, sediment control laws.

Emerging issues With Construction Permitting

Another recent change with respect to construction permitting is the addition of monitoring and sampling requirements placed on the construction operator in some states. These monitoring requirements are largely driven by the total maximum daily load (TMDL) program, which requires that impaired waters have detailed plans developed that determine the amount of pollution the water body can withstand and still meet water-quality standards and divide that allocation between pollution sources. Construction activity usually impairs waters though sediment discharged by ineffective or absent BMPs. Historically, construction operators monitored the effectiveness of BMPs through visual inspections and maintenance of practices. General construction permits issued by EPA Region IV and the State of Georgia, however, now require monitoring from certain construction sites.

The EPA Region IV construction permit, issued on April 28. 2000, requires construction operators who discharge to a water body impaired by total suspended solids and listed on the EPA-approved 303(d) list to collect a sample once a month within the first 30 minutes of a rain event of 0.5 in. or greater. This permit is used mainly in the state of Florida and places an extra burden on construction activity in that state, which discharges to these impaired water bodies.

The permit issued by Georgia for all construction activities occurring after August 1, 2000, also requires monitoring and the development of a comprehensive monitoring program (CMP). The CMP, prepared by a professional licensed by the State of Georgia, must include a map showing each stormwater outfall and streams, a list of receiving waters, and a narrative of the sampling and analytical methods used to collect and analyze the

Summary