The Fox River Agency downstream from us in Illinois dredges on a continuing basis. The immediate area around a hydraulic dredge is of the order of one acre, which boats may not enter while the dredge is at that location. The hydraulic dredge is also trailed by a plastic pipe about one foot in diameter, through which the sediment-water mixture is pumped to the dewatering site. This is typically kept at the surface by floats. Efforts would be made to route the pumping pipe such that it would minimize its effect on boat navigation. For example, on a relatively wide bay such as Island View Bay and Buena Lake, the pipeline would most likely run down the middle instead of along one side, to minimize blockages of piers.
There would be temporary navigational inconveniences in the immediate vicinity of the dredge and the pipeline. Both would change locations as the project proceeds. Detours would sometimes be necessary. The most severe case would be when the pipeline needs to cross the river. In such a case, effort would be made to schedule the blockage for early spring or late fall, when few boats are out, and its time minimized. “Temporary” here refers to durations of a few weeks; certainly not years.
At this point in time, we do not know exactly where the pipelines will go. The dewatering sites and disposal sites are still in the process of being firmed up. The above is just a brief description based on witnessing hydraulic dredging by the Fox River Agency in Illinois.