Maryland's Stormwater Management Program
Looking for information concerning the Tentative Determinations to issue NPDES stormwater permits to Baltimore City, Prince George's County, Baltimore County, and Anne Arundel County? Click here for details.
Stormwater Design Guidance - Environmental Site Design and Innovative Technology (May 2013) Click here for details.
Looking for information on the “2011 Maryland Standards and Specifications for Soil Erosion and Sediment Control” and recently adopted regulatory changes? Click here for details.
Looking for NPDES Permit guidance on accounting for stormwater wasteload allocations and impervious acres treated? - Please click here!
Why Stormwater Matters: Impacts of Runoff on Maryland's Watersheds
Urban development has a profound influence on the quality of Maryland’s waters. To start, development dramatically alters the local hydrologic cycle (see below). The hydrology of a site changes during the initial clearing and grading that occur during construction. Trees, meadow grasses, and agricultural crops that intercept and absorb rainfall are removed and natural depressions that temporarily pond water are graded to a uniform slope. Cleared and graded sites erode, are often severely compacted, and can no longer prevent rainfall from being rapidly converted into stormwater runoff.
The situation worsens after construction. Roof tops, roads, parking lots, driveways and other impervious surfaces no longer allow rainfall to soak into the ground. Consequently, most rainfall is converted directly to runoff. The increase in stormwater can be too much for the existing natural drainage system to handle. As a result, the natural drainage system is often altered to rapidly collect runoff and quickly convey it away (using curb and gutter, enclosed storm sewers, and lined channels). The stormwater runoff is subsequently discharged to downstream waters such as streams, reservoirs, lakes or estuaries.
Water Quality is affected by the accumulation of trash, oil and rubber from cars, fertilizers and pesticides applied to lawns, sediment from bare or poorly vegetated ground and other pollutants entering streams, rivers and Chesapeake Bay. Inflow of sediment can cloud water, blocking sunlight from submerged plants. Sediment also settles to the bottom of streams, clogging the gravel beds used by fish for laying their eggs. Nutrients from fertilizers, such as phosphorus and nitrogen, enter the water and promote unusually rapid algae growth. As this algae dies, its decomposition reduces or eliminates oxygen needed by fish, shellfish, and other aquatic life for survival.
These are all examples of nonpoint source pollution, one of the major contributors to the degradation of water quality in Maryland. Stormwater management practices help control nonpoint source pollution through the use of nonstructural and/or structural techniques to intercept surface runoff from developed areas, filter and treat this runoff, and then discharge it at a controlled rate. The overriding condition that governs the quantity of stormwater runoff is the amount of impervious surfaces located on your property (driveways, roofs, carports, sidewalks, etc.). Stormwater quality, however, is governed by the accumulation of pollutants on the entire surface area, regardless of whether it is grassed or paved. As the use of chemicals around the home such as fertilizers, pesticides, engine oils, deicing materials, and similar products increases, the more degraded the stormwater runoff from your property will be. Although the effect of one property on the quality and quantity of stormwater runoff may seem insignificant, the cumulative impact from hundreds of thousands of yards across the State continues to be destructive to our water quality.
These Activities Will Minimize Stormwater Runoff from Your Property:
- Limit the amount of impervious surfaces in your landscape. Use permeable paving surfaces such as wood decks, bricks, and concrete lattice to allow water to soak into the ground. Where possible, direct runoff from impervious surfaces across
- Allow "thick" vegetation or "buffer strips" to grow alongside waterways to filter and slow runoff and soak up pollutants.
- Plant trees, shrubs, and groundcover. They will absorb up to fourteen times more rainwater than a grass lawn and they do not require fertilizer. For more information on environmentally-friendly planting and "Bayscaping", contact the United States Fish and Wildlife Service, Chesapeake Bay Field Office, or the Alliance for the Chesapeake Bay here:
United States Fish and Wildlife Service, Chesapeake Bay Field Office
Alliance for the Chesapeake Bay
These Activities Will Reduce Fertilizer, Pesticide, and Sediment Runoff:
- Use natural alternatives to chemical fertilizers and pesticides. If you must use fertilizers or pesticides, test your soil to determine the appropriate amount. For more information, contact the Maryland Cooperative Extension Service at 1-800-342-2507.
- If a lawn care company services your lawn, make certain it is not applying "blanket" applications of fertilizer and pesticides. Ask if they have conducted soil tests and a pest analysis to determine appropriate applications.
- Resod or reseed bare patches in your lawn as soon as possible to avoid erosion
Maryland's Stormwater Management Program
Stormwater Management Act
The “Stormwater Management Act” (Act) became effective on October 1, 2007. MDE is responsible for implementing the Act and it's provisions for improving stormwater management in Maryland. More information on the Stormwater Management Act may be found here:
Maryland's Stormwater Management Act
Stormwater Management Regulations
The regulations governing Maryland's stormwater management program, Code of Maryland Regulations (COMAR) 26.17.02, are available from the Office of the Secretary of State, Division of State Documents (DSD) (www.dsd.state.md.us). The official regulations may be accessed through DSD's website here:
2000 Maryland Stormwater Design Manual
The 2000 Maryland Stormwater Design Manual, Volumes I & II is available in print for $25.00 per copy. This is the official version and includes changes made prior to adoption. The Design Manual also may be downloaded in "PDF" format here:
2000 Maryland Stormwater Design Manual
Watershed Protection and Restoration Program
The Watershed Protection and Restoration Program (HB987) was signed into law in April 2012. The program establishes a system of stormwater remediation fees and a local watershed protection and restoration fund (WPRF) that must be implemented by counties and municipalities that are subject to a National Pollutant Discharge Elimination System (NPDES) Phase I Municipal Separate Storm Sewer System (MS4) permit in Maryland. More information on the Watershed Protection and Restoration Program may be found here:
Watershed Protection and Restoration Program Fact Sheet
Stormwater Design Guidance
MDE has published guidance on various technical procedures and calculations relevant to implementing environmental site design (ESD) for both new development and redevelopment. The following publications provide additional information for use when designing or reviewing stormwater plans:
Stormwater Management Guidelines for State & Federal Projects
MDE maintains the publication entitled "Maryland Stormwater Management Guidelines for State & Federal Projects". These Guidelines supplement the Stormwater Management Regulations (COMAR 26.17.02) and the "2000 Maryland Stormwater Design Manual, Volumes I & II". The Guidelines provide information necessary for submittal of stormwater management plans by State and federal agencies to MDE's Water Management Administration for review and approval. The guidelines may be downloaded here:
Guidelines for State & Federal Projects
Questions about the Guidelines should be directed to Mr. Jim Tracy at (410) 537-3666 or by email at James.Tracy@maryland.gov.
Standard Plan for Poultry House Site Development on the Eastern Shore - MODEL
MDE, in conjunction with the Maryland Department of Agriculture (MDA), the Natural Resource Conservation Service (NRCS), and the Soil Conservation Districts (SCDs) has published the “2011 Model Stormwater Management Standard Plan for Poultry House Site Development on Maryland Eastern Shore.” The Standard Plan is a single design option that is intended to be used by the SCDs, County stormwater management authorities, and local designers to address stormwater requirements for poultry operations on the Eastern Shore.
MDE also has developed a stormwater management “calculator” to assist in sizing of the stormwater management practices for the “Model Standard Plan for Poultry House Site Development on the Eastern Shore.” Copies of the model standard plan and calculator are available here:
Model Stormwater Management Standard Plan for Poultry House Site Development
Calculator for Poultry House Development
Erosion and Sediment Control
All Regulated Projects Must Comply with the Revised Stabilization Requirements Beginning January 9, 2013
Maryland’s revised erosion and sediment control regulations, effective February 6, 2012, and the 2011 Maryland Standards and Specifications for Soil Erosion and Sediment Control establish more stringent stabilization requirements for regulated projects across the State. The following portion of COMAR, Section 26.17.01.08G, allows for grandfathering provisions for certain projects:
G. Grandfathering of approved plans.
(1) This chapter applies to all projects that do not have final approval for erosion and sediment control plans by January 9, 2013.
(2) A plan that has received final approval by January 9, 2013 may be reapproved under its existing conditions if grading activities have begun on the site by January 9, 2015, with the exception of stabilization requirements.
(3) Stabilization practices on all projects must be in compliance with the requirements of this chapter by January 9, 2013, regardless of when an erosion and sediment control plan was approved.
This notice is a reminder that all regulated projects must comply with the revised stabilization requirements beginning January 9, 2013. These requirements include shorter timeframes for the temporary and permanent stabilization of all inactive, disturbed areas; specifically three (3) calendar days for perimeter sediment controls and slopes steeper that 3:1 and seven (7) calendar days for all other areas not under active grading.
Statewide compliance with these regulations will help limit the adverse impacts associated with erosion and sedimentation during construction and serve to protect water quality in Maryland’s streams and Chesapeake Bay. If there are any questions regarding this, or any other issue related to erosion and sediment control, please call the Sediment, Stormwater, and Dam Safety Program at 410-537-3543.
Erosion & Sediment Control Guidelines for State and Federal Projects
MDE is pleased to provide the "Maryland Erosion and Sediment Control Guidelines for State and Federal Projects" on the Department’s web site. Supplementing the Erosion And Sediment Control Regulations (COMAR 26.17.01) and the “1994 Maryland Standards And Specifications For Soil Erosion And Sediment Control”, the Guidelines provide information necessary for submittal of erosion and sediment control plans by State and federal agencies to MDE's Water Management Administration for approval. The guidelines may be downloaded here:
Erosion and Sediment Control Guidelines for State and Federal Projects
Questions about the Guidelines should be directed to the Sediment, Stormwater And Dam Safety Program at (410) 537-3543.
Manual for Erosion & Sediment Control On Forest Harvest Operations
For nearly thirty years, timber cutting in Maryland's forests has been regulated for erosion and sediment control. In 1977 the Maryland Department of Natural Resources (DNR), Water Resources Administration (the predecessor of MDE’s Water Management Administration) developed the regulatory document: Soil Erosion and Sediment Control Guidelines For Forest Harvest Operations In Maryland. It continues in use today virtually unchanged from that time.
The 2005 Maryland Erosion and Sediment Control Standards and Specifications for Forest Harvest Operations, maintains the fundamentals of the original 1977 guidelines. Appropriate revisions have been made to bring them in line with current agency names, COMAR citations, etc. In a few instances substantive issues have been addressed. A summary of changes provides more detail as to what we have done in the draft document to make it current, suitable as standards and specification, and for inclusion by reference in COMAR. Both the revised draft document and the summary of changes are available in pdf format here:
2005 Maryland Erosion and Sediment Control Standards and Specifications for Forest Harvest Operations
Maryland's NPDES Municipal Stormwater Permits
The Environmental Protection Agency’s (EPA) National Pollutant Discharge Elimination System (NPDES) stormwater regulations were published in 1990. Phase I of these regulations require large (greater than 100,00 in population) urban jurisdictions to control pollution in stormwater to the maximum extent practicable. Municipalities with less than 100,000 are permitted separately under Phase II NPDES stormwater rules.
Click here for more information on Maryland's NPDES Municipal Stormwater Permits.
Guidance for Maryland's NPDES Stormwater Permits
NPDES municipal separate storm sewer system permits in Maryland require the restoration of a certain percent of a jurisdiction's impervious surface area (e.g., 20%) that has little or no stormwater management. How to calculate impervious surface requirements and treatment credits has generated numerous questions. This document standardizes procedures for reporting of traditional, new, and alternative best management practices (BMPs) and the impervious area each controls. The draft guidance may be found here:
"Accounting for Stormwater Wasteload Allocations and Impervious Acres Treated"
Car Washing Fundraisers
Car washes are a popular means of raising money for worthwhile causes (e.g., scout troops, sports teams, school clubs, charities). However, the runoff from washing cars, if not properly managed, can adversely impact local waterways. When conducting car wash fundraisers, follow these guidelines to prevent washwater from flowing untreated to Chesapeake Bay and its tributaries. More information is found on the fact sheet:
Facts About Car Washing Fundraisers
Chemical Deicers and Chesapeake Bay
Winter weather such as snow and ice may make travel conditions treacherous. Ensuring mobility and safety during icy weather is a priority for local governments, businesses, and homeowners. As snow piles up, the first response should be to shovel sidewalks and plow streets to keep them clear and prevent ice from forming. When ice does become a problem, salt (sodium chloride) is the most commonly used deicer. While it is a popular choice for melting snow and ice, salt can have an adverse effect on the environment. More recently, many other deicing products have been tested and used. More information on the effects of salt on the environment and alternative chemical deicers is available on the fact sheet:
Facts About Chemical Deicers
Please direct comments or questions concerning Maryland's stormwater management program to the Sediment, Stormwater And Dam Safety Program at (410) 537-3543 or email at Brian.Clevenger@maryland.gov
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