Silt Fence is a System Silt fence is a system. The system is only effective operating as a unit. Placement is important because where a fence starts, runs, and ends is paramount to gathering and detaining water. As little as 6 inches can miss a major vein of water, or allow water to run around an end and wash out the slope, making the fence a complete waste of money and causing more damage than no silt fence. Proper placement is often accomplished by creating an upturn, called a J-hook, on the end of a run to insure the water is detained for sedimentation to occur.
Quantity refers to the proper ratio of silt fence to area protected.
A good ratio is 100 linear feet of silt fence per 10,000 square feet of area. Improper quantities have a direct relationship to silt fence failures. Installation refers to the proper installation of fabric in the soil, and the creation of optimum conditions for compaction once installed. Again, a silt fence improperly installed is a complete waste of money. Fabric needs to be embedded deep enough in the soil to prevent under-cutting.