Mississippi's Oktibbeha County Lake Dam found vulnerable to failure

The Oktibbeha County Lake Dam located in eastern Mississippi is prone to collapse due to intense precipitation that struck the region.

According to an official statement issued on January 14, 2020, the water level in the lake increased by at least 30 centimeters in just one night after heavy rainfalls hit the area. Currently, the lake covers an area of about 364 hectares while its ordinary surface is just 172 hectares.

Engineers that inspected the dam suggested that it is vulnerable to failure and that the nearby residential area should be immediately evacuated. A potential failure would flood about 7,000 hectares of land and affect 112 residences.

According to Clyde Pritchard, Oktibbeha County engineer, vast quantities of water are discharged downstream from the dam's spillway while 4 siphons that move water from the lake to a nearby stream have been installed. Additional pumps were delivered on January 17, 2020, and attempts to reduce the water-level are underway. However, this procedure could last for weeks or even months.

The high water level has resulted in seepage in the dam. Water has penetrated the structure and reached the dry part of the dam resulting in a small landslide due to the pore-water pressure increase. According to officials, the slide is currently being monitored and has been stabilized.

Authorities monitor the structure's integrity every time rainfalls strike. The last time that the dam was inspected (in 2016), it was rated as "fair" but a report issued about the dam's integrity outlined that seepage problems existed. According to Kristen Campanella, Oktibbeha County emergency management director, repairs should have been implemented, however, there were no funds secured during the past years. The total amount needed to completely fix the dam is $8 million.

Two sinkholes have emerged near the dam but they remain stable.

The U.S. National Weather Service predicts that Mississippi River will reach flood level during January at Arkansas City (Arkansas), Greenville, Vicksburg and Natchez (Mississippi). Record precipitation has been recorded in Jackson (11,4 centimeters), Meridian (5,2 centimeters) and Vicksburg (8,9 centimeters).

Recently, two dam failures occurred in Mississippi and South Carolina. The Holmes Lake Dam located in Hinds County, Mississippi, failed on January 3, 2020, due to deficiencies found in the construction process. Earlier, in December 2019, a dam in Aiken County, South Carolina, was severely damaged after intense rainfalls struck the region and water level increased in the surrounding lake.

Officials implemented an emergency plan and have closed the gates of the Steele Bayou control structure. "We are currently experiencing higher-than-normal water stages across the region. We've activated our Emergency Operations Center to monitor the forecasted flows and its impacts on our infrastructure. The district has begun and will continue to work with its local, state and federal partners," Colonel Robert Hilliard, Vicksburg District Commander, stated.