The Mississippi River dropped some more Monday as the local dredge vessel moved upriver for more specialized work to keep the thoroughfare navigable.

The gauge at the river bridges at Vicksburg read 1.28 feet at midmorning, four-tenths of a foot lower than Monday. The record low in the city is negative 7 feet, on Feb. 3, 1940. Its record height came last year, when it climbed to 57.1 feet on May 19 during the historic flood. The river stood at 24.9 feet in Vicksburg on this date last year.

Dredging by the U.S. Army Corps of Engineers and commercial outfits has kept the Lower Mississippi navigable despite the low stages. The Dredge Jadwin and three contract vessels continue dredging, despite built-in limitations, Corps spokesman Kavanaugh Breazeale said.

“The Jadwin isn’t designed or funded to do ports,” Breazeale said. “The Corps of Engineers is only doing this to help out local areas.”

The Corps dredger moved out of Madison Parish Port Monday after silt was moved twice to deepen the channel, he said. It’s on to Greenville next, where barges have run aground, he said.

Stages there dipped two-tenths of a foot this morning, to 8.54 feet. The Port of Vicksburg, located off the river’s main stem, is scheduled to be dredged in September as part of $6.84 million in emergency work there and five other shallow-draft ports on or near the river.

A forecast last week from the Lower Mississippi River Forecast Center in Slidell, La., put the river at a tenth of a foot in Vicksburg by mid-August. A new, four-week outlook is expected by 1 p.m. Wednesday.

No closures of the channel are imminent, the Coast Guard has said. The main channel, in the middle of the river roughly between piers 3 and 4 on the old U.S. 80 bridge, is expected to remain open, Breazeale said. Ports are the high priority, he said.

Some restrictions on barge traffic are possible at zero or a high-negative stage, but won’t stop altogether, according to hydraulics officials with the Vicksburg District. The ease of navigability is determined “at different levels at different areas of the river,” Breazeale said.