Sediment Containment During In-Water Pile Driving

A continuous length of silt curtain, fully surrounding the pile-driving area and installed close to piers, will be used to protect aquatic resources and provide sediment containment while construction activities are occurring if working in a wetted channel. The silt curtain will prevent the release of a turbidity plume and trap sediment that may become suspended as a result of the pile driving. The bottom of the silt curtains must be weighted (e.g., with ballast weights or rods affixed to the base of the fabric) to resist the natural buoyancy of the silt curtain fabric and lessen its tendency to move in response to currents. Floating silt curtains will be anchored and deployed from the surface of the water to just above the substrate. The silt curtain will be monitored for damage, dislocation, or gaps and will be immediately repaired where it is no longer continuous or where it has loosened. The silt curtain must restrict the surface visible turbidity plume to the area of pile construction and must control and contain the migration of resuspended sediments at the water surface and at depth.

These IWW-011 measures may be waived or modified by the USFWS Field Office when pile driving involves only non-self-propelled, hand-driven methods (e.g., using a hand-held manual or pneumatic pounder) and commensurate small diameter pile material (e.g., nontreated tree stakes less than 5 inches in diameter).