Posted on September 28, 2021
The Army Corps of Engineers just wrapped up the dredging of the mouth of Lake Ferguson and timing could not have been better.
The Mississippi River hit its lowest point of the year this week, and without the dredging, operations at the port would have been at a standstill.
“The water is low, but we just got the dredging done in time,” said Tommy Hart, Greenville port director. “The port would not have been able to operate without the dredging.”
Each year, the Army Corps of Engineers dredges from the mouth of Lake Ferguson to about 1,000 feet north at a cost of about $1 million per year.
During the high-water season, as much as 2-5 feet of sediment is deposited at the mouth of the lake.
“It’s an issue created by the high water,” Hart said. “The water swirls at the mouth and deposits sediment there.”
The dredging operation pumps the sediment back in to the river for it to be washed down stream.
The lowest predicted point this last week was 14.7 feet, and while low, it isn’t the lowest mark in the last five years.
In 2015, the river bottomed out at 11.5 feet. The highest low-water mark was 23.2 feet in 2019.
Since 1941, the lowest mark on the river was 7 feet according to Mississippi Levee Board chief engineer Peter Nimrod. At 7 feet, all traffic was stopped on the river.
“No issues on the levee — but it is a navigation concern,” Nimrod said. “Barges might have to be light loaded — costing more to ship grain. Everything is good on the levee.”
On May 3, 2021, the Dredge Jadwin, with a crew of around 50 U.S. Army Corps of Engineers (USACE) Vicksburg District team members, departed from the Vicksburg Harbor for its annual season of dredging along the Mississippi River and its tributaries.
Col. Robert Hilliard, Vicksburg District commander, and Patricia Hemphill, Vicksburg District Deputy District Engineer for Programs and Project Management, visited the Dredge Jadwin the morning of its departure to meet with crewmembers and speak with them about safety.
“I couldn’t be prouder and more appreciative of the hard work and dedication of the Jadwin crew,” said Hilliard. “Their safe return is what’s most important as they embark today. People are at the heart of what matters most and when we take care of them, the mission will get accomplished.”
The Mississippi River has served as the lifeblood for our country throughout its development from an agrarian to an industrial society. People settled and built their farms along riverbanks. Cities grew up around farms, and eventually industry made its way to where it could efficiently and economically ship and receive goods. Even today, a host of industries and major cities spill out from the river’s edge, bolstering tourism and economies.
Dredges serve to clear sediment in rivers which falls out where the current slows. Locations with slower current are typically channel crossings and harbor entrances. The unique features of a dustpan dredge help it to clear a path, making channels passable.
Dustpan dredges have a dustpan-shaped appendage which lowers to a specific depth on the river bottom. The water jets agitate the sediment and the dustpan vacuums up the agitated material and pumps it through the dredge and pipeline, where it is typically placed in swift water and resuspended as it continues its journey down river. The material can also be placed in a deep location if the current is not strong enough to wash it down river.
To dredge a specific location, the Jadwin uses two 5,000 ft. cables which are crisscrossed and sunk by anchors weighing 6,000 lb. each. The cables help the Jadwin to maneuver while dredging. Winches pull against anchors to advance. A dredge tender (towboat) is also used to assist in moving left and right.
There are only four dustpan dredges total in the United States, and three of those, the Jadwin, Potter, and Hurley, belong to the Corps of Engineers. The fourth dredge is owned and operated by a private contractor.
The dredge season typically begins as soon as the spring water rise is over in April or May and ends some time in November. In the off season, dredges undergo critical repairs and maintenance.
Because of back-to-back years of high water and flooding, last year’s dredging season was record-setting at 247 days.
For more than 28 years now, Chuck Ashley has called the Dredge Jadwin his home-away-from-home. He started in 1994 as a deckhand and worked his way up to boat operator on a tender, to 2nd mate, pilot trainee, assistant master and has served as the captain of the vessel for the past 3.5 years.
“There’s no other country like ours in the world,” Ashley said. “Strategically, the Mississippi River is a viable resource to the United States. If you buy fuel in Memphis, it likely came out of the Mississippi River. If you’re a farmer with grain, it travels on the river, too.”
The USACE Vicksburg District encompasses a 68,000-square-mile area across portions of Mississippi, Arkansas and Louisiana that holds seven major river basins and incorporates approximately 460 miles of mainline Mississippi River levees. The Vicksburg District is engaged in hundreds of projects and employs approximately 1,100 personnel.
(Dredging information obtained from the U.S. Army Corps of Engineers Public Affairs department.)