Corps Completes Mississippi River Emergency Dredging
St. Paul District’s hydraulic dredge, Dredge Goetz, works to clear a shallow portion of the navigation channel near Wabasha, Minn., on July 30, 2014. High water events in June brought in significant amounts of sedimentation, filling in the channel as the river level returned to normal levels. (Photos by George Stringham, USACE)
In July, LS Marine Inc. of Vadnais Heights, Minnesota, joined the U.S. Army Corps of Engineers St. Paul District on the Mississippi River to reopen the waterway following June floods.
Navigation on the river was closed in areas where the depth dropped below nine feet, which in many places was the width of the channel. The dredges worked from July 16 to August 7, removing more than 290,000 cubic yards of material from the river.
Two Corps’ hydraulic dredges, Goetz and Dubuque, and mechanical dredge Hauser/Wade dredged in a nine-foot deep navigation between Wabasha, Minnesota, and Alma, Wisconsin, in Pool 4, after high flows from flooding in June caused dredged material to fill in parts of the channel. Dredging also took place in Pool 6, near Winona, Minnesota. At both locations, the Corps and its contractor dredged temporary pilot channels, and the channel remained closed to commercial traffic until the dredging was complete. The channel near Wabasha was first closed July 19 due to shallow conditions and July 23, near Winona.
Tender Boat McNamara brings an empty barge alongside the St. Paul District’s mechanical dredge Hauser/Wade on July 29.
The Dredge Goetz is 225 feet long by 39 feet wide by eight feet deep, with a five-foot draft. It has 22-inch suction pipe with a 20-inch diameter discharge pipe. In total, it has 4,010 hp. The district christened the dredge on June 24, 2005, and it cost $9.8 million. The dredge has no hydraulic systems onboard and AC motors driven by Caterpillar 351B engines. The dredge maintains 850 miles of the Upper Mississippi River, 355 miles of the Illinois River and 24 miles of the St. Croix River.
LS Marine operated two mechanical dredges in the channel, and the Corps also had two survey boats to monitor dredging operations.
To reopen the channel, the dredges dug a 200-foot pilot channel, beginning on July 16, where the waters had receded. Authorized channel width is 300 feet. Dredging on Pool 4 was completed August 7, and the channel in Pool 6 was reopened August 3.
The Fluekiger, a tender boat assigned to the Dredge Goetz, adjusts the pipeline that’s moving slurry to the Grand Encampment disposal site along the Mississippi River near Wabasha, Minnesota, on July 30, 2014.
High water from flooding in June carried with it large amounts of sediment, and when the flows reduced, the sediment settled out of the water. The 290,000 total cubic yards that was removed is nearly 30 percent of the average material removed during an entire year. Regular maintenance dredging along the river will continue into fall.Edit Module