Silt Curtains as a Dredging Project Management Practice

摘要

The term 'silt curtain' is used to describe devices deployed in water to control suspended solids or turbidity resulting from dredging operations. Almost every silt curtain application has unique features that require site-specific adaptations. Several sources of published technical guidelines and best management practices are identified and referenced in this note. Typical topics covered in these guides include planning considerations (site-specific project conditions), design criteria, construction specifications (curtains and other materials), installation or deployment, removal, and maintenance. A notable exception is monitoring of silt curtain performance. For cost considerations, logistical constraints, and performance expectations, prevailing current velocities of 1 to 1-1/2 knots effectively limit deployments, with exceptions on a case-by-case basis. Unfortunately, few comprehensive studies are published on the actual performance of silt curtains under varying project conditions. Additional monitoring studies will be required to properly document the functional characteristics and incremental costs of silt curtains under demanding project conditions of moderate to high currents, winds, and waves. Silt curtains should not be considered a 'one solution fits all' type of best management practice. They are highly specialized, temporary-use devices that should be selected only after careful evaluation of the intended function and should be designed based on a detailed knowledge of the site where they will be used.