The U.S. Army Corps of Engineers (USACE) Vicksburg District says the Yazoo Backwater area is predicted to crest at 98 to 98.5 feet within the week. Vicksburg District engineers increased the forecasted crest in the Yazoo Backwater area from its original forecast of 97.5 to 98 feet due to prolonged high water on the Mississippi River, resulting in an extended closure of the Steele Bayou Control Structure, and in consideration of the field data collected.
The Vicksburg gage on the Mississippi River has been above flood stage for more than 90 consecutive days, which is the longest duration that the gage has been above flood stage since 1927. As of May 18 at 6 a.m. Central, the Vicksburg gage on the Mississippi River was at 49.6 feet.
The National Weather Service forecasts indicate that the Mississippi River will crest near 49.8 feet on the Vicksburg gage by May 20th. The elevation of the Yazoo Backwater area, on the landside of the Steele Bayou Control Structure, was at 97.8 feet, while the elevation on the river side of the structure is 97.8 feet. The elevation in Eagle Lake, Mississippi, adjacent to the Muddy Bayou Control Structure is 93.4 feet and rising.
If the Yazoo Backwater area reaches 98 to 98.5 feet, the Vicksburg District anticipates that Eagle Lake may essentially have enough water flowing into it to equalize with the backwater area, resulting in a potential elevation of 98 to 98.5 in Eagle Lake within the next seven to 10 days. This increased forecast will cause additional roads overtopping near the lake and water moving into residences below an elevation of 98 to 98.5 feet near the lake.
The Vicksburg District will continue to monitor stages on the Mississippi River to determine when conditions are such for the opening of Steele Bayou. The district is advising the local community to remain vigilant and aware of the rising water level.
The Steele Bayou Control Structure, which was built in 1969, combined with the Mississippi River and Yazoo Backwater levees, prevents the Yazoo and Mississippi rivers from backing up and further flooding the Delta. The Steele Bayou Control Structure’s gates are opened when elevations on the Yazoo River fall below the elevation of water in the interior Yazoo Backwater area.
Under normal operations, the Muddy Bayou Control Structure’s gates are opened (allowing water to drain from Eagle Lake) when the Yazoo Backwater area’s elevations fall below the elevation of water in Eagle Lake. The Steele Bayou Control Structure was closed Feb. 15th, reopened April 1st to allow gradual drainage of the Yazoo Backwater area and then closed again May 11th.
Due to well above average rainfall in the region since February 2019 combined with a prolonged high-water event on the Mississippi River, limited flows have drained from the Yazoo Backwater area while structures were opened. In March 2019, the interior Yazoo Backwater area reached its highest elevation since 1979. With the Yazoo Backwater area rising daily, this record stage will continue to be surpassed until the crest.