The National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) Permit Program is an EPA regulatory program administered in Maryland by the Maryland Department of the Environment (MDE). The program is intended to reduce and eliminate pollution from rainfall runoff, which flows through storm drain systems to local streams, ponds, and other waterways. Specifically, the goal of the MS4 Permit program is to restore and maintain the chemical, physical, and biological integrity of the nation's waters, as defined in the Clean Water Act, by controlling previously uncontrolled sources of pollution across the landscape that are transported by rainfall runoff or stormwater.
Learn more about stormwater pollution.
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NPDES MS4 Permit Requirements and Implementation
The Maryland Department of the Environment is responsible for issuing all NPDES permits in the state of Maryland. (The state of Maryland has the authority to issue permits on behalf of EPA.)
DEP is the lead department coordinating a multi-department/agency response to meet the requirements of the stormwater permit issued to the County by MDE. The permit is a key driver of the County's strategic watershed management program. Here are the key permit terms, followed by how the Department of Environmental Protection (DEP) seeks to address them:
1. Complete restoration efforts for an additional 20 percent of the County's impervious, urban surfaces not currently restored to the maximum extent practicable.
DEP programs to meet this requirement include:
For the Anacostia watershed, the County will work to establish a trash pollution baseline within one year, implement a trash abatement program, expand education to citizens, and monitor efforts to ensure that programs continue to progress toward a trash-free Potomac. County-wide programs to meet these challenges include:
3. Implement TMDL limits to restore impaired waterways in the County by developing and implementing plans to reduce nonpoint source pollutant loads (e.g., from stormwater). Ensure anti-degradation measures for high quality waters (Tier II waters) within the County including appropriate reviews prior to approval of capital projects, water/sewer plan amendments and any development with the potential to affect water quality and downstream water quality.
Pollutant limits are determined through quantitative analyses referred to as Total Maximum Daily Loads (TMDLs).DEP programs that implement TMDL limits include:
View maps of County watersheds with approved TMDL load limits and County watersheds with Tier II waters (outstanding waters) subject to anti-degradation rules.
4. Establish long-term schedules for identifying sources of pollution and water quality improvement opportunities for all watersheds in the County.
DEP programs to identify pollution sources include comprehensive physical, chemical, and biological water monitoring programs.
5. Use environmental-site design/low-impact development as a method to capture stormwater, by improving the County's stormwater management ordinances/regulations and modifying the County's planning and zoning codes as needed. Environmental Site Design (ESD) as outlined in Chapter 5 of the Maryland Stormwater Management Act (PDF, 129 pp, 4.8Mb) is required to be implemented to the maximum extent practicable.
Environmental Site Design involves managing stormwater on individual development or redevelopment sites in a decentralized manner as opposed to the traditional approach of concentrating stormwater runoff and conveying it through pipes and hardened channels to large-scale, regional ponds or basins. The approach seeks to slow runoff and mimic a site's predevelopment hydrology by using landscaping features and other techniques. DEP's programs to meet this requirement include:
This comprehensive approach to reducing stormwater runoff uses a combination of enhanced planning techniques, alternative permeable covers, vegetative buffers, and small-scale treatment practices to address the impacts associated with development. Programs to meet this requirement include Environmental Site Design/Low-Impact Development.
7. Detect and eliminate illegal, non-stormwater discharges into the storm drain.
DEP programs to meet this requirement include code enforcement against illegal dumping and water pollution.
8. Involve and engage the public in the process of stormwater control.
DEP is developing a comprehensive outreach strategy on stormwater education and public involvement. Get involved in the Watershed Restoration Implementation Strategy.
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Required NPDES MS4 Permit Steps and Timeline
Step 1: Develop a plan within one year of permit issuance (2009-2010).
- Identify projects, programs, monitoring, and funding needed.
- Develop a schedule for monitoring, tracking, and implementation to meet restoration and pollutant reduction goals.
Step 2: Implement the plan over the 5-year permit term.
Step 3: Collect data and track the results of watershed restoration techniques.
Step 4: Evaluate and modify the plan according to scheduled intervals, using the data collected.
Step 5: Report annually on implementation progress and stream resource improvements.
The Permit requires DEP to submit an annual report to MDE with required report elements (PDF, 2 pp, 16K) on compliance in six areas:
- Legal authority
- Source identification
- Discharge characterization
- Management programs
- Program funding
- Assessment of controls
Current Permit: Annual Report
(All appendicies are available on request, please contact email@example.com)
Previous Permits: Annual Reports
- NPDES Annual Report - 2007-2009 (PDF, 90 pp, 3.6Mb)
- NPDES Annual Report - 2006 (PDF, 90 pp, 2.3Mb)
- NPDES Annual Report - 2005 (PDF, 76 pp, 2.3Mb)
- NPDES Annual Report - 2004 (PDF, 108 pp, 5Mb)
- NPDES Annual Report - 2003 (PDF, 84 pp, 1.5Mb)
- NPDES Annual Report - 2002 (PDF, 79 pp, 2.5Mb)
- NPDES Annual Report - 2001 (PDF, 61 pp, 1.2Mb)
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