STORMWATER

When it rains, water accumulates on man-made surfaces such as roads, roofs and parking lots. These hard (impervious) surfaces prevent the rain from soaking in. As more houses, roads, and shopping centers are built, more water runs off the impervious surfaces and enters our streams and other waterways, either directly or through urban storm drain systems. This water is called stormwater or urban runoff, and it eventually finds its way into the Chesapeake Bay.

Stormwater carries a host of contaminants from the land into the water: sediment, phosphorus, nitrogen, toxic metals, herbicides and pesticides, organic material, oil compounds, and bacteria. Roadways, for example, release oil and grease, tailpipe emissions, and other toxics from motor vehicles. Lawns contribute fertilizer and animal waste. Construction sites release quantities of mud.

As impervious surfaces channel large quantities of rainwater into streams at high velocity, the runoff wreaks havoc. The flow scours stream banks, destabilizes stream contours and alters depths. It muddies drinking water sources and also carries bacteria, making the treatment and use of such water more expensive.

In the Bay's tributaries, eroded material and dirt from the land become suspended in the water, blanketing aquatic habitat. Sediment keeps sunlight from reaching underwater grasses. As these plants die, the animals that rely on them are imperiled.

Stormwater pollution is responsible for about 19 percent of the nitrogen and phosphorus pollution in the Bay, if the contribution of nitrogen from air pollution is included. It is one of the major reasons that the Bay remains on the EPA's "dirty waters" list.

How to Address Stormwater Pollution

The Chesapeake Bay Foundation (CBF) strongly believes that the best strategy for reducing stormwater pollution combines three elements.

1. Planning and zoning phase
   This is when local jurisdictions decide where to permit development, how much development to allow, and where and how to conserve land and preserve open space. Steering development away from sensitive areas and watersheds, where stormwater pollution and construction could do the most harm, is the goal.
2. Design
   CBF advocates strong construction and post-construction stormwater regulations at the state level.  For construction (erosion and sediment control), for example, we believe there should be much shorter time frames for covering exposed soil, and a smaller construction area open at any one time than is currently allowed. For managing stormwater after construction is complete, we believe urban sites should manage for full "water quality volume" (about an inch). Also, new development on previously undeveloped sites should manage for full "channel protection volume"—with some leeway for problem sites.  Stormwater management should use low impact and environmental site design techniques that mimic natural hydrology and use infiltration to the maximum extent practicable. CBF also advocates for strong, progressive municipal stormwater permits.
3. Enforcement
   All these techniques and processes need to be mandated, and backed by adequate compliance review and enforcement by local and state governments. If construction sites are not adequately monitored and the requirements are not strictly enforced, development can cause enormous damage to nearby streams. Also, if in-place best management practices (BMPs) are not regularly inspected and required to be maintained after development is complete, their ability to continue to function cannot be guaranteed.
   CBF advocates strong federal, state, and local laws, regulations, and programs — and their vigorous implementation — to prevent and reduce stormwater pollution in Pennsylvania, Maryland, and Virginia. Such laws and regulations should incorporate conservation planning and should feature infiltration as the primary method of treatment.

How to Improve Existing Stormwater Regulations

The federal Clean Water Act (CWA) requires the largest municipalities to obtain and hold permits for their stormwater discharges (called "Municipal Separate Storm Sewer System Permits," or MS4s). At the local level, stormwater issues are being raised by groups of concerned citizens.

CBF has increased its outreach efforts in the three Bay states to join with more watershed groups and assist them in stormwater abatement advocacy. This effort emphasizes education about stormwater, its causes, and ways to prevent or reduce its effects. CBF helps watershed groups create advocacy strategies to address stormwater pollution in their local streams and waterways, which in turn will reduce pollution of the Chesapeake Bay.

How you can help

In Virginia: Join our Team Mudbusters Program. Learn about proposed revisions to Virginia's stormwater regulations.

In Maryland and Pennsylvania: Learn more about Erosion and Sediment Control Problems and Join the Get The Dirt Out Program of Waterkeepers Chesapeake

At Home:

• Detach your downspouts to prevent them from flowing into municipal storm drain systems. Install rain barrels to collect the flow instead. 
• Create "pervious" walkways and driveways (of crushed stone, mulch, or other materials) that return rainwater to the ground. 
• Reconfigure your yard to create rain gardens in low-lying areas.

Additional information about stormwater management can be found at the following websites: 
The Center for Watershed Protection
Low Impact Development Center 
Low Impact Development Urban Design Tools