Background
Congress amended the Clean Water Act in 1987, requiring a program to control nonagricultural stormwater discharges. Environmental Protection Agency (EPA) focused the program on significant causes of water quality impairment. The targeted sources include runoff from urban areas and certain industrial activities, including construction. The result is the National Pollutant Discharge Elimination System (NPDES) Stormwater Program, a two-phase initiative.
Phase I requires stormwater permits to address runoff from three sources. These sources are most major municipal systems, some construction activities, and ten kinds of industrial activities. Phase II expands the program, requiring permits for some smaller municipal storm sewer systems in urbanized areas. Another part of Phase II is inclusion of more construction activities. Permits come from the NPDES authority, be it a state or regional EPA office.
Key Concepts
Municipal Separate Stormwater System (MS4)
A conveyance or system of conveyances used for collecting or conveying stormwater. A public body must own the system. If it is part of a combined sewer system or publicly owned treatment works, it is not an MS4.
Large, Medium, and Small MS4s
A system serving a population of more than 250,000 people is a “large MS4.” A system serving between 100,000 and 249,000 people is a “medium MS4.” A “small MS4” serves fewer than 100,000 people. Small MS4s are exempt from the Phase I program, unless specifically regulated (see below). The NPDES authority can supersede these categories as necessary, regardless of population served.
Regulated Small MS4s
Small MS4s located in “urbanized areas” serving more than 50,000 people are automatically included in the program. A population density of 1,000 per square mile also results in inclusion. The NPDES authority can bring any small MS4 into the program.
Industrial Activities
Ten categories of industrial activity, plus construction, require NPDES stormwater permits. A list of these categories is in 40 CFR 122.26. Hazardous waste treatment, storage, and disposal facilities (TSDFs), some airports, and steam-based electric generation facilities are in this list.
Construction Activities
Any activity that exposes the soil to erosion is construction for the purposes of these rules. This includes clearing, grading, excavation, or removal of vegetation.
NPDES General Permit
General permits are a common set of requirements for a broad range of stormwater discharges. For example, a state might issue a General Permit for Construction Activities. Then, individual construction projects apply for coverage under the General Permit for a certain amount of time. This saves the state from issuing a new permit for each project.
Stormwater Management Program
This is a plan designed to reduce or eliminate pollutant discharges and protect water quality. These plans must be developed, implemented, and enforced by certain MS4s. A program must include six minimum control measures, measurable goals, and periodic evaluation. These programs may result in local requirements to control stormwater in situations not covered by the NPDES authority.
Stormwater Pollution Prevention Plan (SWPPP)
A SWPPP is required for every construction project that requires NPDES permit coverage (5 acres or more without exception, between 1 acre and 5 acres with an option for a waiver). The plan must include runoff control measures, pollution prevention, and best management practices. The plan must also include site drainage and discharge maps, inspection procedures, and reports.
Does this apply to my campus?
If your campus owns its own stormwater drainage system, the “regulated small MS4” regulations may apply to you. The results of the 2000 Census may trigger new regulations for many small MS4s. Local populations may surpass 50,000 and become “urbanized areas.”
If you perform or contract for construction that affects 1 acre or more, the SWPPP regulations apply to you. Evaluate construction activities on a case-by-case basis. The context of the overall project is the deciding factor. Even if the project disturbs less than 1 acre at a time, a total scope above 1 acre requires a permit. Some projects may be eligible for waivers.
What do I have to do?
First, identify the local NPDES permitting authority in your area. It will probably be a state agency, but it may be the regional EPA office. The permitting authority will set the specific compliance dates for Phase II requirements.
If your college campus meets the definition of regulated small MS4s, you will need to apply for a NPDES General Permit. Any institution that meets the definition of an MS4 must develop, implement, and enforce a stormwater management program as outlined by EPA.
The NPDES permitting authority for your area may be flexible with implementation options, such as allowing an institution to cooperate with its local municipality for its program.
A regulated small MS4 may be able to obtain a waiver from Phase II program coverage if it serves fewer than 10,000 people and meets a variety other requirements. There are fewer requirements for regulated small MS4s that serve fewer than 1,000 people.
For construction activities that affect more than 1 acre, the institution or the general contractor must obtain a NPDES permit. To obtain a NPDES permit, you must file a Notice of Intent, develop a SWPPP, and post a public notice. At the close of the project, the institution or the general contractor must submit a Notice of Termination.
The contractor or institution may be able to apply for a waiver for projects that affect between 1 and 5 acres. To obtain the waiver, your project must meet two primary conditions. The institution or contractor must certify both that control of stormwater is unnecessary and that there is a low rainfall erosivity factor. You or your contractor can use total maximum daily loads (TDMLs) or equivalent analyses for this statement. There is no waiver option for projects over 5 acres.
If your campus operates a Resource Conservation and Recovery Act-permitted TSDF for storage or treatment of hazardous waste, a steam-based electric generation utility, and/or an airport, those operations should be integrated into a stormwater permit.