These two photos show silted stormwater runoff resulting from a lack of erosion and sediment control measures during residential construction. Photo © Krista Schlyer/iLCP
Solutions for Addressing Polluted Runoff—Construction
The Chesapeake Bay Foundation (CBF) advocates strong construction and post-construction polluted runoff regulations at the state level. CBF also advocates for strong, progressive municipal stormwater permits. We believe that the best strategy for reducing runoff pollution combines the following four elements. This overview represents the standards CBF advocates; these may be higher than those currently in place in any particular location.
- Prevention: Planning and Zoning—Through comprehensive plans and zoning ordinances, local jurisdictions decide where development should occur, how much development is allowed, and the amount of open space or working land in a community must be conserved or protected from such development. Steering development away from sensitive areas where polluted runoff does the most harm and protecting wooded and other open spaces that can naturally filter rainwater are both critical strategies for reducing stormwater pollution levels in the Bay.
- Design, Construction, and Post-Construction—Once development is approved and goes forward an important consideration is the design and construction of the specific sites. These elements are often controlled by local subdivision, stormwater, and sediment and erosion control ordinances. A site under construction is a potential hot-spot for polluted runoff. Unless effective erosion and sediment control measures are designed well and adequately implemented, a rainstorm can wash large amounts of sediment and debris into the nearest stream, impairing local water quality. It's crucial to minimize both the amount of soil and the amount of land exposed, as well as the amount of time time soil is exposed to the elements. The latter should be no more than 72 hours after construction temporarily or fully ceases.
Once construction is complete, redevelopment projects should manage their sites and buildings for the full "water quality volume" of stormwater—about an inch of runoff, more or less, across the Chesapeake Bay watershed. New development projects should manage for full "channel protection volume," a greater amount of water; this prevents runoff from adversely affecting nearby streams. New development sites should also use "low impact" and "environmental design" techniques (also called "green infrastructure") that mimic the natural flow and filtration of water, if at all possible.
- Enforcement—Ordinances, construction management practices, and environmental side design standards are meaningless unless people follow them. When construction sites are not adequately monitored and requirements are not strictly enforced, development can cause enormous damage to nearby streams. If polluted runoff management practices are not regularly inspected and maintained long after construction is complete their ability to function properly cannot be guaranteed.
- Permits—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). Most of these permits in the Chesapeake Bay region are outdated (meaning more than five years old) and have been administratively continued pending new ones. As a result, many of these permits still have old and weak requirements. Even the new ones are not as accountable as they should be.
Outdated permits are currently a problem for 10 out of 11 of Virginia's largest municipalities, and six of 10 of Maryland's largest local governments. Pennsylvania's communities in the Bay region, like many smaller towns and counties in Virginia and Maryland, are covered by a different kind of permit that has less specific water pollution control requirements.
Maryland and Virginia's environmental agencies have pledged to update and strengthen the permits for large counties and cities in 2014 to help meet pollution limits for the Chesapeake Bay. Stronger runoff permits will help the states implement the Chesapeake Clean Water Blueprint, to reduce pollution from all sources, and clean up local streams. Urban and suburban polluted runoff is a local problem begging local solutions and promising local benefits, as well as larger benefits to the Chesapeake Bay.
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
(Photos, from top: © 2010 Krista Schlyer/iLCP; © Susan Zox, courtesy Hendrick Smith Productions)