VICKSBURG – Water levels in the Mississippi River remain low, causing headaches for shippers who have to go to extra steps to load and unload cargos at docks where shallow water is preventing the barges getting all the way to the dock.
Emmett Neal, director of marine operations at Magnolia Marine Transport Co. of Vicksburg, said rain in Mississippi earlier in October wasn’t much help with low water levels in the Mississippi River.
“It hasn’t really gotten better,” Neal said. “The rain that we receive here just doesn’t have that much impact on water levels of the Mississippi River. It may downriver, but not here. Where we have to have rain is the upper Mississippi Valley and the Ohio Valley in order to raise the water levels here.”
Neal said in many cases currently they are having to load and unload cargo but putting a spacer barge between the barge and the dock. The spacer barge is empty, floating higher in the water allowing it to make it up to docks where the water is too shallow for fully loaded barges.
“Without the spacer barge, you can’t get the loaded barge to dock to discharge product,” Neal said. “We don’t have this at every dock we visit, but are seeing more of it all the time. It creates scheduling problems because we don’t always have extra barges available to serve as spacer barges. It makes the job a little more difficult.”
The water levels from the drought of 1999 haven’t reached levels as low as in 1988 when shipping was stopped on portions of the river due to drought conditions. Shipments were delayed for weeks in some cases, with companies seeing losses of $10,000 per day for each towboat.
Neal said currently the U.S. Coast Guard is doing a great job of keeping people on the inland waterways advised of areas of shallow water where conditions might be difficult. He also credited the U.S. Army Corps of Engineers (COE) with doing the best possible to keep navigation channels open.
“I think the Corps does a tremendous job with the funding levels they have,” Neal said. “Our industry works a lot in conjunction with the Corps lobby in Congress to keep Corps funding at the necessary levels. It is a constant fight each year to get necessary funding.”
Mississippi River ports handle more than 40 million tons of cargo annually, a figure that is expected to double by the year 2000. Waterborne transportation is touted as being the most environmentally friendly way to transport commodities because it takes less energy to transport the materials, and keep hazardous materials off the highways.
The Vicksburg District of the U.S. Army Corps of Engineers (COE) has developed new management strategies that are reducing the amount of dredging needed to maintain navigation, something that is particularly helpful with low water conditions such as seen with the drought this year. Less dredging also saves money in the long run.
With the new engineering technique, stone dikes protrude into the river that keep the channel defined more clearly. As river levels fall, the water scours out the main channel to keep it open to navigation.
“Using dikes and revetments have greatly decreased the amount of dredging needed,” said Jim Jeffords, chief of navigation for the Vicksburg District of the COE. “Instead of having a river a mile wide, it narrows it down in low water conditions so it scours itself out. In the late 1980s we were dredging in the Vicksburg District two to three months per year. In the past five years we have only dredged two weeks per year.”
A revetment is an erosion control method which materials, in this case an articulated concrete mattress, is laid over the embankment to fix the bank in a permanent location. The dikes provide nesting areas and habitat for the least tern, an endangered species, and some dikes contain notches that allow water flow behind the dikes to create fish habitat.
Years ago revetments were made by tying willow trees together. That was followed by using asphalt mats. Concrete mats are now favored because they are quick and easy to put down once the dike has been graded. Concrete mats are now being installed on an area of the river near New Orleans.
Jeffords said the new river maintenance techniques mean that low water levels aren’t as much concern as in the past. There are a couple areas on the river that don’t scour out as well as other areas, and those still have to be dredged. Currently such an area near Natchez is being dredged.
“We continue to look at the river regularly,” Jeffords said. “When we see a portion of river that we have to dredge, we look at it, do a survey, and make a model to see what can be done to master plan to eliminate the dredging part of it. It is a unique operation.”
In 1988 several areas in the Vicksburg district were blocked to navigation for several days because of low water levels. Between 50 to 100 tows were backed up near Greenville. One barge contains the equivalent of 58 18-wheel trailers.
Contact MBJ staff writer Becky Gillette at firstname.lastname@example.org.