Silt Fence Quantity
Quantity refers to area of control. A good rule of thumb is a maximum of 100 linear ft. per 10,000 sq. ft. of area. A one inch per hour rain event produces 6200 gallons of water on just 10,000 sq. ft., so for effective design, utilize multiple runs (smiles) to create multiple storage areas, which also reduce the flow velocities.
Avoid long runs of silt fence. They usually concentrate the runoff in one area and overflow the fence. Restrict length of runs to less than 200 linear feet.