The Silt Wing Excavator - An Innovative Sediment Leveling and Grading Device

The Houston Ship Channel (HSC) and the smaller channels intersecting it require maintenance dredging on a routine basis. Historically, dredging there has been performed using cutterhead dredges with dredged materials placed in Confined Disposal Facilities (CDF) for retention and management. In recent years, innovative sediment management tools have become commercially available to manage sediment shoals at projects where site conditions are suitable for their use. One of these tools, the SILT Wing Excavator, a patented device from the United Kingdom has been operating in the United States at Greens Bayou on the Houston Ship Channel for redistributing soft materials within the channel. There are distinct advantages to using these water jetting devices: there is no dredged material to be placed in a CDF for costly management; the systems are capable of operating in relatively busy channels without unduly interrupting waterborne traffic; and costs may be lower than traditional dredging operations. Disadvantages to the use of these sediment management tools include: the maintenance materials must eventually be removed from the system; bottom materials to be removed by these dredges and site conditions of the projects must be suitable; and there is a question of impacts on water quality associated with their use. The Corps of Engineers, under its mission to identify and demonstrate innovations in dredging technologies, observed the SILT Wing Excavator in operation and made monitored the resuspension of sediments into the water column. This paper describes the technology, presents examples of the results of the demonstration project at Greens Bayou, and outlines plans for future observations of this and similar sediment management devices being considered for demonstration by the Corps of Engineers.