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New goals for improving water quality in the Chesapeake Bay watershed may run into conflict with “smart growth” principles that encourage concentrating new development in existing urban areas.
In addition to making urban projects more difficult, stormwater regulations usually make infill development more expensive than a similar project built outside of the urban area, noted NAHB Environmental Policy Analyst Glynn Rountree.
In some cases, storm water requirements for urban projects may be impossible to meet without readily available off-site alternatives to achieve compliance, he said.
Under Maryland’s two-month-old stormwater management effort, redevelopment projects that are at least 5,000 square feet in size and where more than 40% of the site is impervious pavement are required to reduce the amount of impervious surface by half or else find a way to successfully treat at least 1 inch of runoff when it rains.
During a meeting held by Maryland’s Department of Planning in January, Maryland home builders, local municipalities, the Maryland Municipal League, the Maryland Association of Counties and other groups expressed their concerns that the new requirements for urban projects might be so difficult that builders would decide instead to build outside of the cities.
Small infill sites offer little room for water treatment systems and limiting the amount of impervious surface reduces the housing, sidewalks and parking permitted on the site while adding significantly to the cost of the homes, Rountree said.
Partly as a result of that meeting, Maryland added offsite stormwater mitigation alternatives to its stormwater rule — including water quality trading programs and the payment of additional fees that can be used to pay for the treatment of stormwater runoff in other locations.
“Time will be needed to determine the overall impact of Maryland’s new stormwater rule,” Rountree said.
“When the Chesapeake Bay Total Maximum Daily Load is proposed in September, builders in the Chesapeake Bay watershed will need to scrutinize those new requirements to ensure that, once again, development in the urban areas is provided with the flexibility necessary to comply with the new storm water rules,” he said.
In general, Rountree noted a trend around the country toward more stringent water pollution reduction measures for construction activities in urban areas.
Challenges for new infill projects include:
- Space constraints, limiting materials and vehicle access and storage at the building site
- Limits on construction activities due to noise or traffic concerns
- Extra precautions due to concerns about contaminated soils
- Soils that are likely to be compacted from previous development, making it more difficult to employ infiltration systems to help manage stormwater
- Less available space to install berms, silt fences and other so-called “Best Management Practices” or stormwater storage sites.
- Requirements for removing or retrofitting impermeable pavements at the building site
For more information, e-mail Glynn Rountree, or call him at 800-368-5242 x8662.
“Storm Water Permitting: A Guide for Builders and Developers,” available through NAHB BuilderBooks, provides a starting point for builders and developers to use in locating and understanding stormwater permitting requirements.
The publication has been prepared to help builders comply with the U.S. Environmental Protection Agency's stormwater requirements, and includes information on state permitting programs and more than 50 of the most commonly used Best Management Practices.
Also included are tips on compliance, including how to handle visits from inspectors.
To view or purchase this guide online, click here, or call 800-223-2665.