Communication Key As Corps Prepares For Low-Water Conditions

The Corps of Engineers is being proactive in preparing for low-water levels in 2023 that could approach those of last year, according to a briefing to the Inland Waterways Users Board (IWUB).

Patrick Chambers, chief of operations and regulatory for the Corps’ Mississippi Valley Division, briefed the board at its July 20 meeting in Paducah, Ky.

Chambers said the majority of the Mississippi Valley experienced precipitation that was 25 to 50 percent below normal in June. That has created moderate to extreme drought conditions throughout the system and looks similar to the same period in 2022, he said.

“We’re going to ride back down to those low stages similar to what we were seeing last year,” he said.

He noted that recent rains have been helpful for the short term, “but in order to get us back in those mean ranges where we’re all comfortable, it’s going to take weeks of rain, based on these drought conditions.”

The Corps is stepping up efforts to combat low water well in advance, he said.

Dredging

There are already 17 dredges operating throughout the system, Chambers said.

“The harbors were heavily impacted last year,” he said. “We made sure that we got a couple of extra dredges so we can dredge more harbors at the same time this year so we don’t get behind the power curve.”

Some port captains were reticent to allow dredging last year because that would have caused a temporary shutdown of the harbor while dredging was taking place, and they wanted to get out as many shipments as possible before the low water shut down operations. This year, Chambers said, the Corps is trying to get ahead by dredging harbors earlier, well before harvest season.

Of the 17 dredges operating, seven mechanical dredges are on the Upper Mississippi. The government cutterhead Goetz is among those, along with the dustpan dredges the Hurley and Potter. Four contracted dredges are at work.

On the Lower Mississippi, the dustpan dredge Jadwin is at work, along with contract cutters working in Memphis and Vicksburg harbors. There is also a contract dustpan dredge, the Wallace McGeorge, focusing on deep-draft work and three contract hopper dredges on the Lower Mississippi, with one of those focusing on deep-draft crossings and the other two at Southwest Pass.

The Vicksburg and Memphis Engineer Districts are each acquiring one additional contract cutterhead dredge for harbor dredging efforts, Chambers said. These additional dredges should be under contract within the next 30 days.

The average age of the government-owned dredges is 70, Chambers said. The Potter turned 90 in 2022, and the Jadwin turned 90 this past February.

Board member Dennis Oakley asked how long it would take to deliver a dredge if it was ordered today. The answer was five to six years.

“That’s scary,” he said.

Maj. Gen. Butch Graham, the Corps’ deputy commanding general for civil and emergency operations and executive director of the Inland Waterways Users Board, pointed out that of the 17 dredges working right now, 10 are contract dredges, and they will continue to be used as needed.

IWUB Chairman Spencer Murphy commented that planning for droughts needs to become a regular occurrence, given how many times in recent years the nation has experienced low-water conditions on its inland waterways.

Graham said those discussions are taking place. He also acknowledged that recapitalizing dredges is a priority.

“We’re going into this realizing this is a marathon, and we’re taking care of our people to make sure we can keep those dredges running,” he said, adding that the White House is also paying attention to the situation.

Before last year’s drought, none had major navigation effects on the system for a decade, since 2012, he said.

“This time we’re much more attuned to the situation because we just lived through it,” Graham said.

He added that keeping the river open is of paramount importance, and the Corps is well aware of that.

“We’ve told them to dredge, dredge, dredge,” Graham said. “We will figure out how to get them the money. That’s the assurances we’ve got. We’re going to keep that river open, and we’re going to do our absolute best to keep those harbors open, and we’re going to keep funding [Chambers] what he needs to deliver on that commitment. We are going to keep that river open. You can count on it. There might be some restrictions from time to time, but that’s our commitment.”

Salt Water Sill

A contractor has also begun construction of a sill across the Mississippi River to halt intrusion of salt water up the river from the Gulf of Mexico.

To block the upriver intrusion of salt water, the Corps through dredging contractor Weeks Marine is building an underwater sill of river sand across the bottom of the ship channel. Similar to last year, the Corps is constructing the sill near Myrtle Grove, La., using sediment from a designated site. In 2022, the Corps built the sill at Mile 64 to an initial height from the riverbed of 55 feet. That sill eroded when river flows increased last fall. The same contractor is building the sill this year as last year, Chambers said. It was expected to be completed no later than August 4, he said.

According to the Corps, salt water moving up the Mississippi River in low-water conditions is a natural occurrence because the riverbed between Natchez, Miss., and the Gulf is below sea level. Salt water, which is more dense than fresh water, moves upriver along the bottom of the river in the shape of a wedge. In normal stages, the salt water wedge is held in check by the flow of the Mississippi River. When the river gets extremely low, however, the wedge travels inland, threatening municipal and industrial water supplies.

This will be only the fifth time the Corps has built the salt water sill. Prior occasions were in 1988, 1999, 2012 and 2022.

Communication

In addition to dredging and building the sill, Chambers said communication continues to be key.

The Corps and the Tennessee Valley Authority (TVA) are in constant communication to try to mitigate oscillations in stage and flow below the Olmsted Lock and Dam, he said, adding that TVA has agreed to optimize operations as conditions allow.

Drawdowns to winter pool of both Barkley and Kentucky lakes began the week of July 6 and should provide some additional flow to both the lower Ohio and Lower Mississippi rivers, Chambers said. The drawdown operations are scheduled to last until early October, pending rainfall.

The Corps is also tracking daily “burn” rates versus “on-hand” funding to inform headquarters of any additional needs.

Bi-weekly meetings with the Lower Mississippi River Committee (LOMRC) and as-needed meetings with the River Industry Action Committee (RIAC) and River Industry Executive Task Force (RIETF) are taking place, along with weekly meetings between the Mississippi Valley districts to prioritize dredging projects. The Corps is working its “low water action plan” in coordination with industry, he said.

Additionally, Chambers said, coordination calls with the Great Lakes and Ohio River Division and with TVA take place daily once the river reaches 14 feet on the gauge at Cairo, Ill., and falling.