Upriver rains may change crest

Published 12:00 am Friday, April 18, 2008

VIDALIA — Two National Weather Service weather models indicate heavy precipitation to areas upriver could prolong or even raise the swollen Mississippi River’s crest.

“Beginning Wednesday, we may develop heavy rainfall over eastern Arkansas and Western Kentucky,” National Weather Service Hydrologist Marty Pope said. “We will have to keep an eye over the upper Arkansas River basin.”

But the wet weather expected to come through the area today will likely contribute to the rising Mississippi River’s already record height, but it is not likely to cause a significant increase, according to experts.

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“The first storm may be more related to the upper parts of the river, which would just keep the (river) system full for a long time,” National Weather Service Hydrologist Marty Pope said. “An inch to an inch and a half of rain could add a couple of tenths of an inch to the river.”

Assuming the crest does not significantly change, it will likely stay at that level for two to four days, and then will begin incrementally decreasing, picking up speed as the river’s level drops, Pope said.

Meanwhile, the levee board is continuing its flood fight along the river.

“I look for the sand boils to continue to get worse, but I don’t think we’ll have any other problems,” Fifth District Levee Board President Reynold Minsky said.

A sand boil is when water pressure from the river forces its way through the ground to the opposite side of a levee. Sandbags are placed in a well around the boil until the water pressure equalizes and stops displacing soil.

The sand boils are located in East Carroll, Madison, Tensas and northern Concordia Parish, Minsky said.

Though there is a visible sandbagging presence in the area, residents should not be concerned, Minsky said.

“There are no problems with the levees, and we don’t need anybody to be concerned,” he said. “The levees are in good shape.”

In Vidalia, the southern end of Front Street has been closed to traffic due to water back-flowing through the drains.

The northern end of the street — where the Vidalia Conference and Convention Center, the Riverpark Medical Center and Comfort Suites are located — is still open, Vidalia Mayor Hyram Copeland said.

The Vidalia riverwalk is still open, and the city will keep it open as long as they can, but it will be patrolled to ensure safety, Copeland said.

Water has risen to within feet of the riverwalk, and waves and wake action from river traffic can actually cause the water to lap against the back porch on the Vidalia Conference and Convention Center.

Because the water is so close to the riverwalk, Copeland said many people might put themselves in hazardous situations because the high water is a change from the normal situation.

“You have got these youngsters who don’t realize how dangerous the high water is,” Copeland said. “It looks like you can just step off there and wade, but you can’t. That’s a swift current.”

The river, which is expected to crest at 57 feet above gauge zero Monday, currently stands at approximately 56.6 feet.

But the water is actually much deeper than that.

Gauge zero, from which the river’s height is measured, is set at 17.5 feet above sea level, which means that if the river is at 57 feet above gauge zero, it is actually 74.5 feet deep.

River forecast models for the Natchez-Vidalia pass are released by the National Weather Service’s office in Slidell, and are generated from an algorithm that considers current river height, weather models and other factors.