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ARS Home » Pacific West Area » Pullman, Washington » Northwest Sustainable Agroecosystems Research » Research » Publications at this Location » Publication #117662
Title: SILT FENCES: AN ECONOMICAL TECHNIQUE FOR MEASURING ONSITE SOIL EROSION

Author
item ROBICHAUD, PETER - USDA-FS
item McCool, Donald
item PANNKUK, CHRIS - USDA-FS
item BROWN, ROBERT - USDA-FS
item Mutch, Paul

Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 4/2/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: There is a renewed interest in measuring hillslope soil erosion under specific land management practices and after natural occurring events like fires. Measuring soil erosion is generally costly and time consuming; expensive equipment, many site visits, and multiple laboratory analyses are the main reasons. The objective of the study was to determine the suitability of using silt fence fabric for collecting hillslope sediment and to devise low-cost, easy to use installation techniques. Silt fence fabric is commonly used as an erosion control device for construction projects and is generally available. Two plots with silt fences were installed in conjunction with the long-term hillslope erosion plots at the ARS-Palouse Conservation Field Station, Pullman, WA. Two winter seasons of erosion data were collected. Trap efficiency of the silt fence was determined by comparing the sediment trapped to that flowing though the silt fabric. Results indicate that the trap was 94 percent efficient the first year and 92 percent efficient the second year. Silt fences combined with tipping bucket rain gage measurements provide an easy, low-cost method to measure hillslope erosion and the types of storms that produced it.

Technical Abstract: There is a renewed interest in measuring hillslope soil erosion after land management practices and natural occurring events like fires. Measuring soil erosion is generally costly and time consuming; expensive equipment, many site visits, and laboratory analyses are the main causes. The objective of the study was to determine the suitability of using silt fence fabric for collecting onsite hillslope sediment. The method would also include a low-cost, and easy to install technique. Silt fence fabric is commonly used as an erosion control device for construction projects and is generally available. Two plots with silt fences were installed in conjunction with the long-term hillslope erosion plots at the ARS-Palouse Conservation Field Station, Pullman, WA. Two winter seasons of erosion data were collected. The plots were 22 m in length by 3.6 m wide. Silt fences were installed across the plot bottom by making an up-slope concave cavity such that runoff could not go around the silt fence. The silt fence fabric was folded to form a pocket for the sediment to settle on and minimize the possibility of undermining. Trap efficiency of the silt fence was determined by comparing the sediment trapped to that flowing though the silt fabric. Results indicate that the trap was 94 percent efficient the first year and 92 percent efficient the second year. Accumulated sediment can be collected and weighed in the field with a portable hanging scale. Various time intervals may be used with this technique, depending on the detail of the erosion rates of interest. Silt fences combined with tipping bucket rain gage measurements provide an easy, low-cost method to measure hillslope erosion and the types of storms that produced it.