Posted on October 19, 2022
By Judith Powers
The Corps of Engineers is employing its three dustpan dredges, cutter suction dredge Goetz, and a mechanical dredge as needed throughout the length of the Lower Mississippi.
Continuing low water levels and at least a 10-day forecast of no rain have created ongoing dangerous shoaling throughout the lower Mississippi from above St. Louis to Head of Passes 95 miles below New Orleans.
On October 17, traffic on the Mississippi River was moving with no restrictions, as Corps of Engineers dredges continued to rotate to new locations as needed. Corps Districts remain in constant coordination with the US Coast guard and the Lower Mississippi River Committee (LOMRC) to monitor the number of problem areas on a daily basis.
The dredges are:
Dredged material is spread out by a baffle at the end of the pipeline for distribution into the river current
The Goetz, cutter suction dredge owned by the St. Paul District, length: 225 feet (68.5m), breadth: 39 feet wide (10.9m); depth: 8 feet (2.4m); draft: 5 feet (1.5m), dredge pipe: 22 inch suction (55.8cm), 20 inch discharge (50.8cm), installed hp: 4,010.
The Hurley: dustpan dredge owned by the Memphis District, with length: 353 feet (107.5m), breadth: 58 feet five inches (17.7m); draft: 7 feet (2.1m); dredging depth: 75 feet 22.9m), pipeline: 32 inches (81cm); propulsion by two diesel engines totaling 5,700 hp.
The Potter,a dustpan dredge owned by the St. Louis District, with a length of 240 feet, 6 inches (73.3m); breadth: 46 feet (14m); hull depth: 9 feet 9 inches (3m), draft: 7 feet six inches (2.2m), suction pipe diameter 38 inches (96.5 cm) and discharge pipe 32 inches (81cm), with a maximum 800-foot-long (243m) discharge, and …
The Jadwin: a dustpan dredge owned by the Vicksburg District, capable of dredging as deep as62 feet 18.9m), with a length of 274 feet (83.5m) , breadth: 53 feet (16.1mm), hull depth: 9 feet 9 inches (3m); and draft 7 feet 6 inches(2.2m), with accommodations for 51 crew members.
On Oct. 17, the Hurley had moved to Beckwith near Cairo at Mile 925 (km 1488), and the Goetz was at Middle Mississippi Mile 194 – 184 (km 312-184)near the confluence with the Missouri River.
A Corps mechanical dredge is also working on the shoaling.
STACK ISLAND TIMELINE
Sand has filled the shipping channel at Mile Marker 485, midway down the Stack Island crossing (shoaled area). The Hurley is on the right, and the small boat Ward sets anchors and otherwise helps the dredge. As the river meanders, it slows down on the inside of the bends, allowing sand to drop out, eventually causing a shoal
On Sept. 28, the Hurley, with Captain Adrian Pirani, Assistant Captain Shawn Rogers and 38 crew members, was at St. Francisville, Louisiana at mile 265 (km 426), and departed bound for the river crossing (cross-channel shoal) at Stack Island at Mile 486 (km 782) – 221 miles, according to Vicksburg District Navigation Section Chief Andy Hall.
Severe shoaling had closed the river, stranding hundreds of vessels and thousands of barges above and below the shoal.
The Hurley worked for 9 days, 24 hours a day and removed nearly 300,000 cy (229,366.6m3) of material from a .6 mile, 300-foot-wide (91.44m) section of the river.
Traffic was restored on Oct. 7 at 11:45 when a northbound tow was sent throughnewly deepened channel.
Marine Machinery Mechanic Ron Tuggle provided DredgeWire with photos of the operation showing the dredge from the discharge end, and the river bend where the low water had exposed the shoaled channel in a wide swath. It depicted the auxiliary vessel Ward, which helps set the anchors that allow the dredge to winch forward into the shoal, liquifying the material with water jets and pumping it through a long discharge into the current.
Powerful water jets inside the dustpan head liquify the adjacent sand to allow the pumps to move it through a long floating pipeline and into the current away from the shoaled area
The Hurley departed Stack Island on Oct. 9 at 06:30 bound for a shoal that had developed near Memphis at Mile 681. It arrived on Oct. 11 at 18:00, at which time a 24-hour closure was enacted. Limited traffic was allowed to pass starting on Oct. 12. Traffic was restored by
Water depth at the Memphis shoal was 9 feet, and the Hurley removed approximately 100,000 cy (76,455 m3) of material to restore a limited depth of 9.5 feet (2.9m). Traffic was restored on Oct. 14.
Corps equipment and personnel performed the data collection for the HyPack* and DredgePack* software, creating charts and real time display for the dredge operators of the work in progress. The Hurley and survey boats are equipped with redundant software for these functions.
*Disclaimer: Any reference to a specific product, process or service does not constitute or imply an endorsement by the U.S. Army Corps of Engineers or the United States Government of the product, process or service, or its producer or provider.
DredgeWire thanks Memphis District Project Delivery Team Manager Vickie Watson and Assistant Chief of Navigation Wade Channell for information on the Memphis section.
Photos by Ron Tuggle
