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Storm Water Management Plan for NSA

What is Stormwater? Stormwater is runoff water from rain or melting snow that flows across the landscape. Runoff flows off of rooftops, paved areas, bare soil, and lawns. Runoff gathers in increasingly large amounts (from puddles, to ditches, to streams, to lakes and rivers) until it ultimately flows into the ocean.

On its journey from puddle to ocean, stormwater picks up and transports many of the pollutants it encounters. These pollutants include dirt, pet wastes, pesticides, fertilizers, automobile fluids (such as oil, gasoline, and antifreeze), deicing products, yard wastes, cigarette butts, and litter, just to name a few. By carrying all these different kinds of pollution into our waterways, stormwater itself becomes a water pollutant.


The campus of the National Security Agency has been referred to by some as a "Concrete Jungle." While not very flattering, this description accurately describes much of our landscape. With every significant rain event, thousands of gallons of stormwater flow down our structures and across our parking lots into storm drains that lead directly into the Little Patuxent watershed and ultimately into the Chesapeake Bay. For this reason, it is very important that we act as good stewards of the environment, working to ensure that stormwater runoff is as pollutant free as possible.

waterThe primary pollutants of concern here at NSAW are gas, oils, grease, nutrients from fertilizer, and sediments from erosion. Oils, gas and grease are deposited on the parking lots from leaky automobiles or they can be spilled by fuel operations such as the re-filling of gas powered equipment. Fertilizers are applied campus wide to keep trees and grass healthy, but spills on sidewalks can end up in stormwater. Soil erosion from deforested and/or construction areas is our greatest potential pollution mechanism and one of our greatest areas of concern. Most people do not think of soil as a pollutant, however, over sedimentation of the Chesapeake Bay has contributed significantly to its declining health. When soil particles end up in the water column, they block sunlight from reaching aquatic vegetation. These plants die off without sunlight and then are not available to provide oxygen. When the oxygen is gone, so are the fish and crabs.

In 2007, the NSA was granted a Phase II Small Municipal Separate Storm Sewer Systems (Small MS4) Stormwater Discharge Permit from Maryland Department of the Environment (MDE). In accordance with EPA guidelines for the National Pollutant Discharge Elimination System (NPDES), this permit allows federal facilities to discharge stormwater to waters of the United States, as long as they design and implement several Best Management Practices (BMPs) which will mitigate the harmful effects of pollutants in runoff. The BMPs selected include:

  1. An agency wide education program to familiarize employees with stormwater issues and to teach them what they can do to reduce stormwater pollution.
  2. A public outreach campaign which will provide details about NSA's environmental program on the out-side web and will direct all visitors to informational sites such as the Environmental Protection Agency and the Chesapeake Bay Program.
  3. A project to identify illicit discharges from pipes and drains within agency buildings.
  4. Construction site runoff control through erosion management strategies.
  5. Building Low Impact Development (LID) areas to catch stormwater before it leaves the property.

The NSA environmental team began to carry out these BMPs early in CY07.

For more information on Stormwater and to find out what you can do in your own neighborhood to prevent stormwater pollution, visit the following web-sites:


Date Posted: Jan 15, 2009 | Last Modified: Jan 15, 2009 | Last Reviewed: Jan 15, 2009