[04/19/01] Water easing back into the banks of the Mississippi River in Minnesota and Wisconsin has to come past Vicksburg on its way to the Gulf of Mexico, but flooding upstream doesn’t always translate to flooding here.

The Mississippi and its tributaries drain more than 40 percent of the continental United States. Melting of snow and ice is causing the upper river to flood. The lower river, however, is able to carry far larger volumes of water without the river leaving its banks.

At Davenport, Iowa, where the Mississippi is causing trouble now, the river’s carrying capacity at flood stage is 162,000 cubic feet per second, according to officials at the Mississippi Valley Division. Under the same bank-full conditions, the capacity of the channel at Vicksburg is 1.4 million cubic feet per second, about eight times greater.

“At this time, nothing bad is expected to happen” at Vicksburg, said Jim Coe, a forecaster at the Mississippi River Forecast Center at Slidell, La., basing that comment on normal rainfall in the Mississippi River Basin.

He said the volume of water in the Upper Mississippi, without significant contributions from the Ohio and Missouri Rivers, can’t cause flooding here.

The Vicksburg gauge reading was 24.5 feet Wednesday and 25.3 feet today with a forecast of a rise to 27 feet by Saturday. Flood stage at Vicksburg is 43 feet.

Coe said there are no significant flows coming out of the Ohio and Missouri at this time, and even the long range forecast only indicates the possibility of an inch to an inch and a half of rainfall over the basin some time after the middle of next week.

The result, he said is a rise in the short term to about 29 feet at Vicksburg and then, possibly to just under 30 feet in the next 2 1/2 to 3 weeks.

As it gets closer and closer to May 1, Coe said, the chance of a flood at Vicksburg gets less and less.