Construction Site Erosion and Sediment (E&S) Control Guide
Proper Construction Control
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Erosion and sediment controls perform three basic functions to keep muddy runoff on a site during wet weather and prevent downstream impacts.
- They keep soil in place and help rain soak into the ground (construction entrance, site stabilization, stockpile protection).
- They filter mud out of water before it runs off the site during rain events (sediment barriers, inlet protection, outlet protection).
- They convey, slow down, and/or treat runoff (conveyance channels, sediment traps).
Here is a brief description of eight important types of controls. Some of this information can be complicated, so visit the Additional Resources page if you have questions.
1. Construction Entrance
A temporary rock or geosynthetic mat located at points where vehicles enter and exit construction sites. Some sites install wash racks near the entrance to wash off mud. This control reduces mud transported onto public roads and other paved areas, where it can be introduced to off-site sewers and waterways.
2. Site Stabilization
Grass (either seeding or sod), mulch, straw, and geosynthetic mats or blankets are used for temporary or permanent soil stabilization. Temporary stabilization must quickly follow the clearing of a site, so that exposed mud will not wash off in a rainstorm. Mulch or straw mixed with grass seed is commonly used for flat areas, and geosynthetic mats or netting are used for areas for steep terrain. Trees, shrubs, and grass are planted as permanent stabilization on finished sites. This control is the first line of defense for preventing introduction of mud into runoff.
3. Sediment Barriers
The most common sediment barrier controls are silt fences and straw bales. Silt fences are long sheets of woven black plastic fabric 2 to 3 feet high that are fastened to wooden or metal stakes. Fabric must be kept taut, erect, and anchored to the ground. Straw bales are staked to the ground end-to-end in a tight row, with no spaces between them. Both silt fences and bales are designed to catch mud on the site and slow rainwater that flows through them.
4. Stockpile Protection
Piles of soil are often stored on the site, and must be protected using the site stabilization controls and sediment barrier controls (see above). This control prevents stockpiled material from leaving the storage area or leaving the site.
5. Inlet Protection
Inlet protection is a barrier or filter placed at the mouth of storm drains, culverts, or sewers. Storm drains left unprotected on or below a construction site can allow mud and other pollutants from the site to flow into public sewers or streams. Drains may be completely capped or protected by rock, sand bags, or the barriers controls noted above. This control is used to prevent mud from entering into a drainage system prior to permanent site stabilization.
6. Conveyance Channels
Stormwater conveyance channels are permanent, designed waterways lined with appropriate vegetation or rock. This control is used to safely convey runoff within or off a site. Roadside ditches are a common example.
7. Sediment Traps
Sediment traps are small ponds created to slow down and store water and allow sediment to settle before water leaves a site. Traps are only temporary, and should be replaced by permanent stormwater ponds that serve the finished development.
8. Outlet Protection
Outlet protection is large, loose, angular rock (called ‘riprap”) permanently placed at the outlet of conveyance channels, sediment traps, and pipes. This control is used to slow down water and prevent erosion at or below the point of discharge.
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