In the Upper Mississippi River: Dredge and Dewatering Wheel in Use for Grand Encampment Island Unloading

摘要

Anyone driving along the Upper Mississippi River must be familiar with the mountains of sand visible on islands and shore sites. These are temporary dredged material placement sites for maintenance material from the river's nine-foot navigation channel. These sites are periodically unloaded to provide more storage capacity. The Grand Encampment Island unloading project, at Upper Mississippi River Mile 756.5, in Pool 4, is underway by Black River Constructors - a joint venture that J.F. Brennan and Hoffman Construction formed to bid on the project. The contract is an experiment by the St. Paul Engineer District of a new way of contracting unloading projects. Historically, the district has dictated the details of removal and transport of sand for island unloading projects, doing all the research, and procuring and designing the fill sites. Finding permanent fill sites for the large amount of material involved was becoming increasingly more difficult. Putting the responsibility on the contractor for finding fill sites or uses for the sand, and allowing the contractor to determine how the material is transported to the end use, has taken some of the pressure off the district.