Another record-breaking season is in the books after the Memphis District’s Revetment Units returned home mid-March of 2023, making it one of the longest seasons had in 20 years.
The Memphis District’s Clearing and Snagging and Bank Grading Units are primarily responsible for preparing Mississippi riverbanks for the placement of articulated concrete mattress (ACM), which is accomplished by the Vicksburg District’s Mat Sinking Unit.
Preparation consists of clearing the Mississippi riverbanks of debris, followed by grading riverbanks to design, from top bank to water’s edge.
This process is completed to stabilize the riverbank and maintain proper navigation channel alignment.
"Protecting the Mississippi Riverbanks helps keep the river at the necessary depth and alignment needed by the thousands of tows traveling up and down the river each and every year, all year-round," Channel Improvement Project Coordinator Andrew Smothers said. "Without this work, the river would shift, creating new, shallow cutoffs too dangerous to safely travel."
In addition to safety, stabilizing riverbanks also helps protect the $1 trillion-worth of annual river activity, while also using the most cost-effective and ecofriendly transportation methods possible: towboats and barges.
However, the extent to which the nation and river industry reaps these benefits is dependent upon revetment operations. Fortunately, last season was a successful one overall.
Beginning at a Vicksburg District job site called Ozark M1, the season officially began on July 18, 2022. Revetment operations went on for nearly eight months, again, making it the longest season in 20 years. Operations concluded in Yellow Bend, Arkansas City, on March 11, 2023.
The season wasn’t just a long one, it was challenging as well; but that didn’t keep the team from getting the job done.
Season totals had the Clearing and Snagging Unit removing more than 42,857 linear feet of riverbank sediment, the Bank Grading Unit grading more than 471,000 cubic yards of material, and the Motor Vessel Mississippi delivering a total of 192,735 squares to revetment work sites.
Overall, the team successfully cleared and sank a total of 18 sites, even with the season being as challenging as it was.
“Low water conditions this year were challenging, forcing us to reposition a dredge in the middle of the season to remove sediment from our loading facility at St. Francisville so we could access our ACM and remove it from the yard,” Smothers added. “That was a first."
Adding to the low water challenges was the Memphis District’s aging bank grader. Having completed just under 75 seasons now, the unit’s engine broke down several times, which in turn led to delays and in some cases, cancellations.
“The condition of the existing plant equipment was our greatest challenge,” Smothers said. “We lost four barges of ACM because of the poor condition of our revetment barges and the bank grader was down 26 days due to catastrophic engine failure.”
Additionally, the Mat Loading Unit was down eight separate times, and 12 of 43 barges were out of service due to disrepair.
The Corps has since invested in its revetment machinery, with the Memphis District recently replacing its legacy Bank Grading Unit with a new 2023 model, Grader 1, on April 11, 2023. The Vicksburg District is also scheduled to replace its Mat Sinking Unit within the next one to two years.
The Memphis District is celebrating its new addition with a Christening Ceremony, scheduled for May 2, 2023, at the Lower Mud Island Boat Ramp in Memphis, Tennessee. Additional details to follow.
For more information related to the Memphis District’s new grading unit, the district’s navigation mission, the regional channel improvement program, and more, visit the Memphis District website at https://www.mvm.usace.army.mil/.