Low-Impact Development Leads to Cleaner Environment, Improved Water Quality
ARLINGTON, VA, January 2010 – Step onto any of the United States Navy's 40 installations in the Chesapeake Bay watershed, and you'll see green. The Department of the Navy has implemented a national policy mandating the use of low-impact development techniques, which has made installations more environmentally and economically efficient to construct, operate, and maintain.
New construction activity at Navy installations presents challenges and opportunities for sustaining ecosystems, including the Chesapeake Bay. Typically, new construction decreases natural vegetation cover and drainage capacity and increases impervious surfaces (roofs, lawns, driveways, roads, parking lots and other hard surfaces). These changes can alter an area's hydrology and result in higher peak flows and greater volumes of stormwater runoff, as well as higher sediment and nutrient loadings in nearby waterways.
Development in the Chesapeake Bay watershed is increasing the quantity of impervious surfaces at a rate four times greater than the rate of population growth. These factors have made urban and suburban stormwater runoff the fastest growing source of pollution to the Bay, and the only type of pollution that continues to increase.
In a global effort to reduce impacts to water quality, the Department of the Navy developed a low-impact development policy to maintain or restore predevelopment hydrology. Low-impact development mitigates the adverse effects of construction projects on water quality by cost-effectively reducing the volume and pollutant loading of stormwater before it reaches the receiving water bodies. Low-impact development makes use of innovative methods to capture stormwater using a combination of retention devices and vegetation. Stormwater is retained and managed at the source, rather than releasing stormwater nutrients and sediment downstream.
A bioswale facility between two parking lots treats runoff at Little Creek Amphibious Base in Norfolk.
The overall goal of the low-impact development policy is no net increase in stormwater volume and sediment or nutrient loading from major renovation and construction projects. To support this goal, as well as reduce reliance on conventional stormwater collection system and treatment options, the policy directs Navy installations to consider low-impact development in the design for all projects that have a stormwater management component.
Low-impact development efforts by the Navy are an integral element of a broader Sustainable Infrastructure Program, currently being implemented throughout the Naval Facilities Engineering Command's Mid-Atlantic Region. The program integrates environmental stewardship into all asset management, capital improvements, public works management and energy programs. The integration of low-impact development practices is one main component of the Sustainable Infrastructure Program.
Twenty-seven major projects the Navy completed in 2009 financial year included low-impact development features. Recent projects include a parking lot at Naval Station Norfolk which capped a waste disposal area and now bio-filters most of its stormwater.
The Navy's policy requires implementation of low-impact development techniques on all major construction projects by 2011, with all efforts to incorporate LID practices in 2008 through 2010.
For more information on Navy environmental programs, visit http://www.navy.mil/oceans
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