Stormwater discharges from developed areas are a major cause of degradation of our nation’s waterways. Stormwater carries many pollutants to surface waterbodies. The increased volume and velocity of discharge from developed areas erodes stream banks and carries excess sediments and other pollutants downstream. In fact, stormwater discharge from urban areas is the primary source of water quality impairment in an estimated 13 percent of streams, 18 percent of lakes, and 32 percent of estuaries nationwide (and is likely a significant — if not primary — cause of impairment in many more).
The U.S. Environmental Protection Agency (EPA) issued regulations in 1990 and in 1999 to protect receiving waters from the harmful effects of stormwater discharges. These Clean Water Act (CWA) regulations require certain stormwater discharges to be covered by a National Pollutant Discharge Elimination System (NPDES) permit.
EPA developed the stormwater regulations in two phases, as directed by the CWA. The Phase I regulation, issued in 1990, requires NPDES permit coverage for large and medium municipal separate storm sewer systems (MS4s) that serve 100,000 people or more, and stormwater discharges associated with industrial activity, including construction activities that disturb five or more acres of land. Nine years later, EPA issued the Phase II regulation, which requires permit coverage of MS4s located in urbanized areas (as defined by the U.S. Census), and smaller construction sites (those disturbing one or more acres of land). Municipal permits require MS4s to develop programs to manage stormwater, including stormwater discharges from new and redeveloped sites.
Since 1990, about 7,400 MS4s have been covered by a NPDES permit. Despite the progress made since that time, stormwater discharges still contribute significantly to water quality impairment in the United States. In 2006, as part of EPA’s review of the stormwater program under the CWA, EPA asked the National Research Council (NRC) to review the stormwater program and recommend ways to strengthen it. The NRC report, finalized in October 2008, found that EPA’s current approach to regulating stormwater “is not likely to adequately control stormwater’s contribution to waterbody impairment,” and recommended several actions the agency could take.
Consequently, the EPA is taking actions to help protect U.S. waterbodies from the impact of stormwater discharges. Some of these actions were informed by the findings in the NRC report.
Strengthening stormwater regulations
EPA has initiated a national rulemaking to better control stormwater discharges from newly developed and redeveloped sites, and enact other regulatory improvements to the nation’s stormwater program. On Dec. 28, 2009, EPA issued a Federal Register Notice that describes some of the regulatory changes the agency is considering. Some of those changes include the following:
- Establishing more specific requirements to control discharges from newly developed and redeveloped sites. EPA is considering requiring that post-development hydrology match pre-development hydrology by using techniques such as infiltration, evaporation, and/or harvesting/use of rainwater. EPA refers to these practices as green infrastructure.
- Designating additional stormwater discharges subject to federal regulation. Currently, only those MS4 discharges covered by the Phase I regulation and those in urbanized areas are required by federal regulations to obtain permit coverage. Although this includes most of the nation’s population, federally regulated MS4s serve only about 2 percent of the land area, and MS4s serving areas experiencing rapid development are currently not regulated. EPA is also considering designating additional stormwater dischargers, such as newly developed and redeveloped sites.
- Establishing requirements to better manage existing discharges (retrofitting), where necessary, to protect water quality. Retrofitting stormwater practices could be especially beneficial in urban environments, where stormwater discharges are a primary contributor to water quality impairment.
- Establishing more specific requirements to protect the Chesapeake Bay from the impact of stormwater discharges. President Obama signed Executive Order 13508 on May 12, 2009, which directs federal agencies to take additional actions to restore the water quality in the Chesapeake Bay. In response, EPA will evaluate additional measures that could be implemented to protect the Chesapeake Bay.
To help inform the rulemaking process, EPA held a number of listening sessions, and conducted a national webcast with more than 2,000 participants. In addition, the agency accepted written comments via the public docket to gain early input on stormwater practices and ideas for revisions to EPA’s stormwater regulations under the CWA. To support this rulemaking effort, EPA is also proposing to survey owners, operators, and developers of sites; MS4s; states; and U.S. territories. The information gathered from these surveys will be used to estimate the impact of any regulatory changes. EPA intends to propose a rule in September 2011 and to take final action in November 2012.
Sediment contained in stormwater discharges is one of the leading causes of water quality problems nationwide. To help reduce water pollution from construction sites, on Dec. 1, 2009, EPA published final effluent limitations guidelines and new source performance standards (the C&D ELG). The C&D ELG, which became effective on Feb. 1, 2010, requires all construction permits issued by EPA or states to incorporate the final rule requirements, which include non-numeric requirements for erosion and sediment control, soil stabilization, pollution prevention measures, prohibited discharges, and surface outlets, as well as numeric effluent limitation of 280 NTU for turbidity for certain large sites.
EPA is working to revise its Construction General Permit (CGP), which will expire on June 30, 2011, to include the requirements of the C&D ELG. EPA expects to issue the draft permit for public comment in the summer or fall of 2010, and the final by June 30, 2011.
MS4 permit improvement guide
In April 2010, EPA issued its “Municipal Separate Stormwater System (MS4) Permit Improvement Guide.” The guide, available at www.epa.gov/npdes/pubs/ms4permit_improvement_guide.pdf, provides suggestions for permit writers on how to develop permit language for each of the six minimum control measures required by the Phase II stormwater regulations, including the following:
- public education and outreach,
- public participation/involvement,
- illicit discharge detection and elimination,
- construction site runoff control,
- post-construction site runoff control, and
- pollution prevention/good housekeeping.
Green infrastructure techniques
EPA strongly supports green infrastructure as an environmentally preferable approach to managing wet weather events. Among other benefits, green infrastructure mimics natural stormwater management conditions such as infiltration, evapotranspiration, and (as a partial surrogate for natural, onsite water storage) capture and use of stormwater. These techniques limit both the pollutant load delivered to surface waters (by controlling stormwater discharges) and the erosive effect on receiving stream channels caused by the volume and velocity of the stormwater discharge itself.
There are additional benefits conferred by some green infrastructure practices such as reduction of the urban heat island effect (through the installation of green roofs), air cleansing and oxygenation (via rain gardens, green roofs, and other techniques involving vegetation), reduced energy use in summer (with green roofs), and aesthetic improvements (increase in green space and preservation of waterbodies).
Green infrastructure approaches are increasingly being incorporated into stormwater management programs. To date, stormwater permits in at least six states — Alaska, California, New Jersey, North Carolina, Ohio, and West Virginia — contain requirements that promote the use of green infrastructure.
On April 19, 2007, EPA and four national organizations (The National Association of Clean Water Agencies, Association of State and Interstate Water Pollution Control Administrators, Natural Resources Defense Council, and the Low Impact Development Center) formed the Green Infrastructure Partnership. Since that time, more than 80 national groups, including the American Institute of Architects, the Gulf Restoration Network, and the U.S. Green Building Council, have joined the partnership in supporting green infrastructure efforts.
To promote the benefits of using green infrastructure to reduce stormwater discharge and mitigate overflows from combined and separate sewer systems, the partnership has developed an action strategy for managing wet weather with green infrastructure. The strategy focuses on encouraging the use of green infrastructure as a prominent component of combined and separate sewer overflow control strategies, municipal stormwater programs, and nonpoint source and watershed planning efforts. To help meet the growing need for professionals trained in green infrastructure methods for managing wet weather events, EPA and the Green Infrastructure Partnership have sponsored many green infrastructure workshops and developed several useful tools and guidance documents to help communities evaluate green infrastructure.
In October 2009, the stormwater program also joined forces with EPA’s Smart Growth Program to release a Water Quality Scorecard, which offers policy options to help local governments identify opportunities to remove barriers to green infrastructure, revise and create codes and ordinances in support of green infrastructure approaches, and find incentives for better water quality protection.
The American Recovery and Reinvestment Act (ARRA) of 2009 required the Clean Water and Drinking Water State Revolving Fund (SRF) programs to allocate 20 percent of their funds to green projects (defined as green infrastructure, energy efficiency, water efficiency, and other environmentally innovative projects). Based on state reporting, the SRFs allocated approximately $1.66 billion to green projects, about $242.8 million of which was allocated to more than 260 green infrastructure projects. Congress retained the green project requirement for the SRFs in the FY2010 budget, designating 20 percent of the $3.3 billion provided to the SRF programs to green projects.
For additional information on any of the topics mentioned and to view the latest news and information about EPA’s stormwater program, visit www.epa.gov/npdes/stormwater or sign up for the agency’s periodic newsletter, NPDES News, at www.epa.gov/npdes/npdesnews
Focus on the Chesapeake Bay watershed
The Chesapeake Bay Compliance and Enforcement Strategy is a multi-state plan for addressing violations of federal environmental laws. More information about the map is available at www.epa.gov/compliance/civil/initiatives/progress-chesapeakebay.html Information about the Chesapeake Bay Compliance and Enforcement Strategy is available at www.epa.gov/compliance/civil/initiatives/chesapeakebay.html
Connie Bosma is the branch chief for the U.S. EPA’s Office of Wastewater Management Municipal Branch. She can be reached at firstname.lastname@example.org.