Barges on the Mississippi River are getting lighter as the river gets lower — a condition unlikely to change until there’s more water to float the boats.

“We continue to run, but we’re lessening on the tows,” said Roger Harris, senior vice president of operations for Magnolia Marine Transport Co. “It’ll probably get worse before it gets better.”

The river dipped to 1.53 feet late Friday, down a foot in 24 hours. In Memphis, stages had plummeted to minus 8.4 feet late Friday.

On Thursday, low water had parked the American Queen steamboat, where about 240 passengers had to take a bus to Vicksburg to finish the boat’s “Epic Civil War” voyage.

The ongoing drought and the hottest July on record have combined to threaten records on the Lower Mississippi. The record low in Memphis is minus 10.7 feet, set in 1988 when part of the river closed. In Vicksburg, the record is minus 7 feet, set in 1940.

Forecasts by the National Weather Service River Forecast Center show the river at Vicksburg dipping to four-tenths of a foot by early September. Negative readings are predicted upriver at Caruthersville, Mo. and Tiptonville, Tenn.