Performance evaluation of two silt fence geotextiles using a tilting test-bed with simulated rainfall

This paper presents the results of the investigation of the performance efficiencies of silt fence fabrics in turbidity and sediment concentration removal, and the determination of flow-through-rate on simulated construction sites in real time. Two silt fence fabrics, (1) a woven type and (2) a nonwoven type, were subjected to material index property tests and a series of field-scale tests. The fabrics were tested for removal efficiency by varying the rainfall intensities and events for different embankment slopes on a tilting test-bed. Collected influent and effluent samples were analyzed for sediment concentration and turbidity, and the flow-through-rate for each fabric was evaluated. Test results revealed that the woven and nonwoven silt fence achieved 14 and 52 percent average turbidity reduction efficiency, and 23 and 56 percent average sediment concentration removal efficiency, respectively. Evaluation of sediment concentration reduction based on percent removal does not correctly account for the sediment concentration transported and deposited downstream. Fabric flowrates were functions of the rainfall intensity, embankment slope and field conditions, and fluctuates with every rainfall event. (C) 2013 Elsevier Ltd. All rights reserved