EPA: Clean Water Act (CWA)
The EPA protects the nation’s water supply through the Clean Water Act. The Clean Water Act establishes the basic structure for regulating discharges of pollutants into the waters of the United States and regulating quality standards for surface waters. Under the CWA, EPA has implemented pollution control programs such as setting stormwater management standards for communities, developments, businesses and residential areas. The EPA has also set water quality standards for all contaminants in surface waters.
Loss of infiltration from urbanization
The porous and varied terrain of natural landscapes like forests, wetlands and grasslands traps rainwater and snowmelt and allows them to filter slowly into the ground. In contrast, impervious (nonporous) surfaces like roads, parking lots and rooftops prevent rain and snowmelt from infiltrating, or soaking, into the ground. Most of the rainfall and snowmelt remains above the surface, where it runs off rapidly in unnaturally large amounts.
Storm sewer systems concentrate runoff into smooth, straight conduits. This runoff gathers speed and erosional power as it travels underground. When this runoff leaves the storm drains and empties into a stream, its excessive volume and power blast out stream banks, damaging streamside vegetation and wiping out aquatic habitat. These increased storm flows carry sediment loads from construction sites and other denuded surfaces and eroded stream banks. They often carry higher water temperatures from streets, roof tops and parking lots, which are harmful to the health and reproduction of aquatic life.
The loss of infiltration from urbanization may also cause profound groundwater changes. Although urbanization leads to great increases in flooding during and immediately after wet weather, in many instances it results in lower stream flows during dry weather. Many native fish and other aquatic life cannot survive when these conditions prevail.
NPDES (CWA Section 402)
The National Pollutant Discharge Elimination System (NPDES) permit program, established under the federal Clean Water Act, controls water pollution by regulating sources that discharge pollutants to waters in the United States. Municipalities are required to apply for NPDES permit coverage in order to operate the storm sewer systems. Under this permit, operators are required to develop and implement a stormwater management program to reduce the discharge of pollutants to the maximum extent practicable to protect water quality.
Communities that do have storm sewer systems must create and enforce a stormwater management program that outlines the minimum standards that must be met in order to satisfy the requirements of their NPDES permit and to ultimately comply with the CWA. There are six minimum control measures for every stormwater management program:
- Public Education and Outreach
- Public Participation/ Involvement
- Illicit Discharge Detection and Elimination
- Construction Site Runoff Control
- Post-Construction Runoff Control
- Pollution Prevention/Good Housekeeping
Minimum Measure #5: Post-Construction Stormwater Management
Controlling post-construction runoff, the fifth minimum requirement of the NPDES program, sets forth more standards for property owners to adhere to once construction is complete.
New development and redevelopment projects that disturb greater than or equal to one acre, including projects less than one acre that are part of a larger common plan of development or sale that discharge into the MS4 must have controls in place that would prevent or minimize water quality impacts. This includes:
- Strategies which include a combination of structural and/or non-structural best management practices (BMPs) appropriate for the community;
- Use an ordinance or other regulatory mechanism to address post-construction runoff from new development and redevelopment projects to the extent allowable under State, Tribal or local law; and
- Ensure adequate long-term operation and maintenance of BMPs.
It is the responsibility of land owners, whether commercial or residential, to manage runoff from their properties. Per federal law, a stormwater pollution prevention plan (SWPPP) is required before any development can occur on their land. This includes site assessment, erosion and sediment control BMPs; good housekeeping BMPs; post construction BMPs; and operations, maintenance, and inspections schedules.
Structural BMPs include: storage practices such as wet ponds and extended-detention outlet structures; filtration practices such as grassed swales, sand filters and filter strips; and infiltration practices such as infiltration basins and infiltration trenches. EPA recommends that you ensure the appropriate implementation of the structural BMPs by considering some or all of the following: pre-construction review of BMP designs; inspections during construction to verify BMPs are built as designed; post-construction inspection and maintenance of BMPs; and penalty provisions for the noncompliance with design, construction or operation and maintenance. Stormwater technologies are constantly being improved, and EPA recommends that your requirements be responsive to these changes, developments or improvements in control technologies.
It is very important the land owner(s) be familiar with the post-construction BMPs onsite, because once construction is complete it is their obligation to maintain them. By adhering to the post-construction criteria set forth in the SWPPP, and understanding the local, state, and federal stormwater regulations, land owners can avoid civil, state, or federal fines.
Most Phase I & Phase II cities (cities with populations over 50,000) require a stormwater utility fee for all property owners in order to fund their stormwater program. These fees are generally based on the amount of impervious surfaces located on the property. Property owners may also be required to install stormwater management facilities on site to mitigate post-construction runoff.
The EPA can take civil and criminal action against any party that is in violation of the Clean Water Act. The EPA can also act in place of state or local governments that are not properly enforcing environmental regulations.