Why do I have to bury the base of a silt fence?

Proper installation and maintenance of silt fence is a critical factor in its success. Any filter cloth is placed on the uphill side of the posts, with the lower edge of the filter cloth of a silt fence buried to minimum depth of 6 inches, and compacted into place. The combination of these two aspects allows the silt fencing to retain and slow the discharge flow of the runoff, causing the silt to “fall” from the runoff and be held by the fencing material.

Photograph of an improperly installed silt fence showing runoff
Improperly installed silt fencing: runoff flowing under fence

When soil is placed over the lower 6 inches of the fencing and it is not buried, the runoff can dislodge the piled earth material, exposing the bottom of the fence. Once the bottom of the fence is exposed, runoff requires little effort to flow under the fencing; rendering it ineffective. To facilitate the success of the usage of silt fencing proper installation and maintenance are required.

Resources

New York Standards and Specifications for Erosion and Sediment Control (Bluebook)

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This work by the Cornell Local Roads Program (CLRP) is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.