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Water Quality: Keeping Pollutants from Going down the (Storm) Drain

By Harry Campbell

You may have noticed a lot of water rushing into storm drains during the heavy rains this past month. This storm water runoff comes from homes, city streets, parking lots, industrial facilities, and construction sites and often contains sediment, fertilizer, pesticides, oil, gasoline, pet waste, or hazardous waste. And because storm water isn’t treated, the runoff that you see flowing into the storm drains is discharged directly into nearby waterbodies along with any pollutants it contains.

Silt Fencing: Best Management Practices for Construction Sites
Silt fencing keeps loose soils contained on site.

Construction activities are a particular concern. We don’t often think of dirt as a pollutant, but it can cause problems for streams and creeks when it washes off a construction site. Because excavation from construction activities removes the protective vegetative layer that holds soils together, erosion at construction projects can occur at 40 times the normal rate. This increased erosion means that storm water runoff from construction sites can easily transport sediment, pollutants, and debris to nearby storm drains, rivers, or lakes. Runoff from these sites can contaminate rivers and streams, harm or kill fish and other wildlife, destroy aquatic habitat, and degrade water quality.

Construction projects that disturb an acre or more — less than an acre if the project is a house lot in a subdivision — are required to get a permit for their storm water discharge. This permit requirement was initially driven by concerns that storms could wash away loose dirt from construction sites, but it has grown to include other sources of pollution from construction activities.

To reduce the risk of storm water contamination at construction sites, permit holders are required to develop a storm water pollution prevention plan (SWPPP) with control measures and pollution prevention (P2) strategies to prevent runoff from washing harmful pollutants into surface waters.

The Division of Water Quality (DWQ) has developed a list of the Top Ten Best Management Practices (BMPs) for construction sites to help contractors reduce pollutant releases into storm water. A little preparation and planning before construction starts can go a long way towards reducing storm water runoff. DWQ’s BMPs for construction sites incorporate the following strategies:

  • Preservation of existing vegetation to reduce erosion
  • Phased construction so soils aren’t exposed for long periods of time
  • Proper management of construction entrances
  • Silt fencing or other perimeter controls to prevent pollutants from leaving the site
  • Storm inlet filters to prevent trash and debris from entering storm drains
  • Protection and installation of vegetative buffers along waterbodies
  • Site stabilization with mulch or vegetation once land disturbance is complete
  • Management of equipment fueling to prevent spills
  • Waste management, including construction solid wastes and paint/concrete cleaning-water waste
  • Fugitive dust suppression
Storm Drain Inlet Protection: Best Management Practices for Construction Sites
Inlet covers keep construction debris out of storm drains

I am the storm water coordinator for construction activity at DWQ, and I urge construction workers to take these simple actions to reduce storm water runoff:

  • Learn where the closest waterbody is to the site. The closer you are to a waterbody, the more diligent you will need to be.
  • Prepare the site to minimize erosion and runoff.
  • Maintain BMPS throughout the construction process.
  • Stabilize the site.
  • Manage vehicles and equipment to minimize spills.
  • Manage waste and materials through proper containment, recycling, and disposal.
  • Leave the site in better condition than you found it.

Erosion control, BMPs, and pollution prevention help ensure that storm water runoff from construction sites don’t add pollutants and sediments to our rivers and streams.

You can help reduce storm water pollution by limiting your use of fertilizers, checking your car for leaks, cleaning up oil or gas spills, washing your car on the lawn, picking up after your pet, avoiding overwatering, and clearing debris away from storm drains. Want to learn more about how storm water permits protect water quality? Check out information about water quality permits for municipal systems, construction activities, and industrial activities on our storm water permit page.
Harry Campbell

I am the Coordinator for the Storm Water Program for Construction Activities at the Division of Water Quality. I have worked in storm water for most of my career. I enjoy working in the storm water program and construction activities. My father was a builder/developer, so I grew up going to work with my father building houses or working at a development.

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