Sediment Pollution

What is sediment?

Sediment is dirt and rocks that move from one place to another via wind or water erosion. Sediment may be made up of small or big rocks and organic matter such as dead plants and animals.

Erosion creates sediment. Wherever erosion happens in a watershed, whether on land or in a streambank, the newly displaced sediment travels toward the closest waterway. It can wash into storm drains and creeks from construction sites, yards, or any location where loose dirt is not secured. It can also detach from stream banks when a rush of rainwater moves from streets to streams during and just after a rain storm.


When sediment pollution enters our streams it often looks like chocolate milk and creates problems. Sediment can harm plants and animals in a natural stream ecosystem. Cloudy water prevents sunlight from reaching native water plants. It also makes it hard for fish and other animals to find their food. Sediment destroys habitat for small animals that live at the bottom of a stream like young fish, dragonfly nymphs, and other aquatic insects. Sediment can also clog fish gills, making it hard for fish to breathe.

Sediment pollution creates problems for humans, too. Sediment transport and buildup can change how the water moves in a stream. It also carries phosphorus, a nutrient that may cause algal blooms. Finally, sediment can lead to bad-tasting drinking water, even after water treatment.

What can you do?

In Durham, stormwater isn't treated before flowing into the nearest creek or stream. Three simple things you can do will help stop sediment pollution: cover, sweep, and call!

Neighborhood with loose dirt in yards. Rain carries the dirt into the street, then the storm drain.

Bare ground leads to erosion. Planting grass or native plants in your yard will help hold the soil in place and promote soil health.

Mulch is another way to help hold dirt in place. Be sure to replace the mulch at least once per year. If you ever have a pile of dirt for a project, cover it with a tarp and secure the tarp corners. That will make it less likely for dirt to blow or wash away from the pile. 

Yards with loose dirt create mud runoff during rainstorms and yards with landscaping don't.

Sweep dirt, excess fertilizer, and yard waste from your driveway, sidewalk, and street. When loose dirt is left on hard surfaces, rain easily picks that dirt up and carries it into the nearest storm drain and eventually the nearest stream. Always sweep dirt off of hard surfaces and back into your yard or a yard waste bin.

Never hose down your driveway! Hosing down your driveway washes pollutants directly into the storm drain system.

Neighbors sweep dirt from hard surfaces back into their yard or garden bed.

If you notice sediment pollution, call the stormwater hotline at 919-560-SWIM (7946). Information to include:

  • What you saw
  • Where it happened (address or nearest street intersection) 
  • Date and time
  • Any additional helpful information

Staff members will investigate to see if a violation occurred and take needed follow-up actions.

 Additional reporting methods include sending an e-mail to [email protected] or using the online reporting form.

A neighbor sees sediment pollution coming from a construction site and calls the hotline to report.

Green Stormwater Infrastructure Practices

Reducing the rush of stormwater runoff that flows to creeks during and after storms prevents sediment erosion. Fast-moving stormwater runoff scours stream banks, sending sediment and nutrients downstream. You can help by keeping stormwater runoff on your property. Rainwater that falls on your roof and yard is a valuable resource for recharging groundwater and watering your plants and grass. Visit our green stormwater infrastructure web page for more information. 

  1. Rain Barrels
  2. Rain Gardens
  3. Stream Buffers

Slow it down.

A rain barrel attached to a house's gutter system helps diminish the amount stormwater runoff. Install a rain barrel or cistern in your yard. Empty the barrels between rain storms so that the runoff has a place to go. This water is useful for watering plants, grass, and gardens. Release captured water slowly between storms to slow down the flow of the water into the storm drain system.