Old Man River can be unpredictable.

A week ago Army Corps of Engineers dredges were removing sand in low areas to keep the river open.

"We were hovering around the minus-10-foot mark on the gauge at Memphis," said Jim Pogue of the corps. That was a record low for the river at Memphis.

"Anytime we get to a minus reading on the gauge we start keeping a close eye on navigation along the river, hoping to keep it open for traffic," said Pogue.

A week later, on Monday, the Mississippi gauge at Memphis was at plus 20 feet. "The water came up almost 30 feet in a week," said Pogue.

Much of the rise was caused by high water along the Ohio River, which joins the Mississippi at Cairo, Ill.

Dike construction that focused on problem reaches of the river and an aggressive revetment program aimed at preventing bank cave-ins have helped keep the channel open, said Pogue.

"Better electronic river surveys and our use of the digital global positioning satellite system also mean we are able to respond with dredges more quickly," said Darian Chasteen, leader of the corps' Memphis District river engineering team.

Two dredges were put to use last week.

The Memphis District dredge Hercules worked just south of Tiptonville, Tenn., and the commercially owned Wallace McGeorge worked south of Memphis.

"The new water eases things for a while," said Pogue, "but we're still watching."

Although traffic has not been halted here recently, the Mississippi has been low since mid-December. Its readings on the gauge at Cape Girardeau have ranged from a low of 7.2 feet to 14.2 feet Monday, the highest reading since Oct. 5 when it stood at 15.4 feet.

December, January and February readings have been near record lows.

For the first time since June 1988, people have been able to walk out to Tower Rock near Wittenberg in Perry County. Tower Rock is a 100-foot landmark that juts out of the Mississippi some 25 miles north of Cape Girardeau. It is listed in the National Register of Historic Places. People can walk to the island that contains the rock when the river gauge at Cape Girardeau is 7.6 or 7.7 feet.

The river stage here was at 7.8 feet Dec. 24 and dropped to 7.2 feet Christmas Day. Since then the river was low enough Jan. 27 and 28 to reach the island by foot and again Feb. 11, 12 and 13, when river stages here were between 7.5 and 7.7 feet.

The river here jumped past the 14-foot mark Monday and could see more water by the weekend. The extended weather forecast calls for showers and thunderstorms throughout Missouri Thursday and Friday.