Sediment and Stormwater

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 the 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, such as phosphorus and nitrogen, from fertilizers 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 quality in Maryland's waterways. 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.

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

The Maryland Department of the Environment (MDE) has reached a tentative determination to issue a National Pollutant Discharge Elimination System permit to Montgomery County to control storm drain system pollutant discharges. MDE has drafted a permit designed to comply with the United States Environmental Protection Agency’s regulations and to control stormwater pollutant discharges from the County’s storm drain system.

A notice for and information concerning the scehduled public hearing may be found here.

On April 24, 2007, Governor Martin O’Malley signed the “Stormwater Management Act of 2007” (Act), which becomes effective on October 1, 2007. Charged with implementation, the Maryland Department of the Environment (MDE) is in the process of addressing the requirements of the Act. More information on the Stormwater Management Act and MDE's efforts to improve Maryland's stormwater management program may be found here.

The regulations governing Maryland's stormwater management program may be found in the Code of Maryland Regulations (COMAR) 26.17.02. The Maryland Department of the Environment, Water Management Administration is pleased to announce the adoption the 2000 Maryland Stormwater Design Manual, Volumes I & II (COMAR 26.17.02.01-1). The effective date of the new regulations and the manual is October 2, 2000. The revised COMAR is available from the Office of the Secretary of State, Division of State Documents (DSD) (www.dsd.state.md.us).

Supplement to the Model Stormwater Management Ordinance

The Maryland Department of the Environment, Water Management Administration (MDE/WMA) has published a Supplement to the Model Stormwater Management Ordinance. This supplement contains optional content for implementing an advanced stormwater management program in Maryland. MDE provides this guidance to assist county and municipal code development as part of local land use and planning to enhance protection of receivng waters, and meet the requirements of the Water Resources Element of local Comprehensive Plans. While all local development review and approval processes are unique, MDE will use this document as a template to ensure effective implementation of advanced stormwater management ordinances.

For a copy of the Model Stormwater Management Ordinance (including the Supplement), please click here! For a copy of the Supplement only, please click here! Questions about the Model Ordinance should be directed to Mr. Stewart Comstock at (410) 537-3543.

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 is also available online and may be downloaded in "PDF" format using the Adobe® Acrobat® Reader.

In accordance with Section 6.0 of the Maryland Stormwater Guidelines for State and Federal Projects, July 2001, all Stormwater Management Facilities require As-Built Plan Certification to WMA upon completion of construction. In addition to the AS-BUILT CERTIFICATION STATEMENT currently required, WMA has developed AS-BUILT TABULATIONS that must also be included on all stormwater management plans.

Beginning JANUARY 1, 2006, these AS-BUILT TABULATIONS shall be required on new stormwater management plan submittals. These tabulations are available here. Questions should be directed to Mr. Jim Tracy at (410) 537-3566.

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.

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 the Chesapeake Bay and its tributaries. For more information, please click here!

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. For more information on the effects of salt on the environment and alternative chemical deicers, please click here.

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 urban jurisdictions to control pollution in stormwater to the maximum extent practicable. For permitting purposes, municipalities with populations of greater than 250,000 are considered “large” and those with populations of between 100,000 and 250,000 as “medium.” Municipalities with less than 100,000 are handled separately under Phase II NPDES stormwater rules. Click here for more information on Maryland's NPDES Municipal Stormwater Permits.

"Maryland's Stormwater Program: Managing for Results" Presentation in PDF Format

The presentation "Maryland's Stormwater Program: Managing for Results" is intended for educating the development community about the use of progressive structural and nonstructural practices in an integrated stormwater design. This presentation is available online here.

In addition to the 2000 Maryland Stormwater Design Manual, the Sediment, Stormwater & Dam Safety Program has several publications related to nonpoint source pollution, stormwater management, erosion and sediment control, and dam safety issues. The list of these publications is available here and may be downloaded in PDF format as well.

MDE has conducted several meetings with local jurisdictions and the regulated community across the State concerning the implementation of the stormwater management program. In response to questions raised during these meetings, MDE will begin offering supplemental guidance for the more common issues on this site. The first subject is the implementation of the channel protection criterion (Cp_v) found in the Design Manual. Click here for more information.

Stormwater management practices help control nonpoint source pollution through various techniques that intercept, filter, and treat runoff from developed areas. MDE recognizes that new structural best management practices (BMPs) are being developed, including many proprietary designs. In response to the growing number of proprietary practices, MDE has published additional guidance concerning the use of these practices within Maryland. This guidance also outlines the basic information that should be submitted to MDE as part of a formal review of new proprietary practices. Click here for more information.

MDE is pleased to announce the publication of the "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, which become effective July 1, 2001, provide information necessary for submittal of stormwater management plans by State and federal agencies to MDE's Water Management Administration for review and approval.

Questions about the Guidelines should be directed to Mr. Jim Tracy at (410) 537-3000.

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.

Questions about the Guidelines should be directed to the Sediment, Stormwater And Dam Safety Program at (410) 537-3563.

Standard Stormwater Management Plan for Single Lot Residential Construction - MODEL

MDE is pleased to announce the publication of a model standard stormwater plan that may be of use to localities implementing stormwater for small development projects. Regulation changes made in 2000 eliminated the exemption for residential developments with average lot sizes of two or more acres. The "Standard Stormwater Management Plan for Single Lot Residential Construction - MODEL" is based on those nonstructural practices found in Chapter 5 of the Design Manual and will help localities provide management to some of those projects exempt from runoff control in the past. If the limitations and conditions of the plan are met and site planning characteristics implemented, this model will address stormwater management appropriately.

Each jurisdiction may use a standard plan. However, all local standard plans must be reviewed and approved by MDE. Localities choosing to use a standard plan should review the model, tailor a similar tool to fit specific permitting processes and submit it for approval.

Questions about the Model Standard Plan should be directed to Mr. Stewart Comstock at (410) 537-3543.


Contact Us About MDE Site Index Privacy Notice Accessibility Translate 1800 Washington Blvd, Baltimore, MD 21230 Tel:(410) 537-3000 Toll Free:(800) 633-6101 Maryland Department of the Environment \| ©Copyright 2002-2008 \| All rights reserved.

Looking for information on the Stormwater Management Act? Please Click Here!