Erosion vs. sediment controls: Prevent stormwater pollution at the construction site
It’s wintertime, and many construction sites across the U.S. face unique challenges that the season brings, especially keeping workers warm! However, one challenge that construction sites face year-round is how to keep stormwater runoff (whether it’s generated by snowmelt or rain) from transporting pollutants off-site into nearby waterways.
Under the National Pollutant Discharge Elimination System (NPDES) stormwater program (40 CFR Part 450), the Environmental Protection Agency (EPA) requires construction site operators to obtain a permit to discharge stormwater runoff into waters of the United States from any construction activity that disturbs:
- 1 acre or more of land, or
- Less than 1 acre of land if it’s part of a plan of development or sale that will ultimately disturb 1 or more acres of land.
Construction sites must implement best management practices (BMPs), which are controls and activities used to prevent stormwater pollution. Erosion controls and sediment controls are the two leading types of BMPs that construction sites have to apply.
Understanding the differences between erosion controls and sediment controls (and how they function together) will help you choose the most effective BMPs to reduce stormwater pollution at your construction site.
Erosion controls vs. sediment controls
Both types of controls are important, but their functions are distinct. Construction sites should use erosion controls as the primary method and sediment controls as the backup method to reduce stormwater pollution.
Erosion controls prevent the land from wearing away. These measures stop soil particles from being dislodged and transported by stormwater or wind. Erosion controls are the first line of defense against stormwater pollution.
Erosion control examples include:
- Shoring excavated areas with retaining walls,
- Conducting construction work in concentrated areas at different times to minimize soil exposure, and
- Installing erosion control blankets on steep slopes.
Sediment controls capture soil particles that have been dislodged (i.e., eroded) before stormwater or wind moves them off the construction site. Sediment controls are the second line of defense, serving as backup BMPs.
Examples of sediment controls are:
- Protecting storm drain inlets with filtering materials (such as rock-filled bags),
- Installing fiber rolls around the perimeter to retain soil dislodged by runoff from small areas, and
- Adding a sedimentation basin to receive dewatering discharges.
Common BMP examples
EPA’s “National Menu of Best Management Practices (BMPs) for Stormwater-Construction” webpage details erosion controls and sediment controls frequently used at construction sites, including (but not limited to) the following:
| Erosion control BMPs | Sediment control BMPs |
|---|---|
|
|
Use both types of BMPs
The most effective way to control stormwater pollution at construction sites is by applying a selection of erosion controls and sediment controls that are coordinated to work together. Consider these examples:
- After an area has been graded, the exposed soil must be stabilized. A site can lay sod over the exposed soil (erosion control) and install a silt fence to catch any contaminated soil moved out of the area by stormwater (sediment control) while the sod takes root.
- Stormwater from upstream locations can flow through a construction site. To protect the disturbed land, a site can build a berm that diverts runoff away from the construction area (erosion control) to a basin where the sediment settles before the runoff is discharged (sediment control).
- When grading an area with a slope, stormwater can transport contaminated soil down the disturbed slope. A site can install a temporary slope drain that directs the runoff at the top of the slope to a pipe that carries it down the side of the slope (erosion control). The site may also add a sediment trap at the slope drain outlet to remove sediment from the runoff before it’s released (sediment control).
Check state and local requirements
Most states issue NPDES construction stormwater permits. Additionally, some local governments may impose requirements on construction sites. However, unless the local program is designated as a qualifying local program, compliance with local regulations may not mean that your construction site is compliant with EPA’s rules (and vice versa).
Check the permit to confirm erosion control and sediment control requirements, as they may be more stringent at the state or local level.
Key to remember: Construction sites must implement erosion controls and sediment controls to prevent stormwater pollution.

















































