The Dirt on Sediment Pollution
What we're doing about this top water pollutant




What's so bad about sediment?
Sediment is the most common pollutant in waterbodies and while erosion is a natural process, man-made erosion causing excessive amounts of sediment pollution can harm ecosystems and degrade water quality.

This type of pollution most frequently comes in concentrated levels from active construction sites, including housing plans, commercial buildings and single family homes.

Sediment pollution directly affects us by causing flooding due to blocked storm drains and catch basins, increasing the cost of drinking water treatment and creating a hospitable environment for toxic algae to grow, making swimmers and boaters sick.

Sediment pollution is also very harmful to wildlife. The water becomes cloudy, preventing animals from seeing food to catch and vegetation to grow. Sediment smothers the habitats of small organisms resulting in a decline in their numbers and the fish that eat them. Also, sediment easily clogs the gills of fish creating lower growth rates, lessening resistance to disease and altering egg development.

What we're doing to prevent it
The E&S staff at ACCD combat sediment pollution both in the office and out in the field. We review construction plans to ensure that installation sequences and proper Best Management Practices (BMPs) are in place to reduce the amount of sediment leaving the site. In the field, we inspect these BMPs to verify they are installed per plan and properly maintained. We may also request that BMPs be added or modified to better protect the surrounding waterbodies. By reducing the amount of sediment in our streams, rivers and lakes, we protect the health of our ecosystem and the health of our families.

More about ACCD's Erosion & Sediment Program
The Clean Water Act prohibits the discharge of pollutants through a point source into waterways unless a National Pollutant Discharge Elimination System (NPDES) permit is in place. The permit limits what can be discharged and requires monitoring and reporting to ensure that discharge does not impact water quality or public health.

Allegheny County complies with Pennsylvania Code Title 25, Chapter 102 for Erosion and Sediment Control. ACCD provides technical assistance and tools to manage and protect land and water resources. More specifically, our Soil and Erosion Program works to minimize sediment pollution into the waterways of the Commonwealth from active construction. Proposed construction that results in over one acre of land disturbance requires a NPDES Permit. In addition, there are some municipalities within Allegheny County that require an erosion and sediment plan approved by ACCD when land disturbance is less than one acre. While these do not require a permit, they do require necessary controls to be installed and maintained on site at all times.

To obtain an approved NPDES permit, Erosion and Sediment Control (E&S) and Post Construction Stormwater Management (PCSM) plan drawings and narratives are submitted, along with a Notice of Intent, to ACCD. These materials are reviewed until deemed complete and in accordance with Chapter 102. While reviewed for completeness, PCSM plan drawings and narratives are not currently approved by ACCD.

Once the NPDES permit is acquired, a pre-construction meeting takes place, per permit conditions, to review the approved plan and expectations for proper control of sediment during construction. Active sites are inspected by ACCD staff throughout the life of the project to verify Best Management Practices (BMPs) are maintained and that the site is operating according to the approved sequence. Once the project is complete, a Notice of Termination (NOT) must be submitted to ACCD and an inspection to verify the site has been completed and stabilized per plan takes place. If all requirements have been met, the site will be terminated from the permit.