The U.S. Army Corps of Engineers (USACE) Vicksburg District (MVK) notified local authorities and emergency management personnel on Thursday of the potential for water to be released at an uncontrolled rate from Arkabutla Lake Dam, which is located 35 miles north of Marks, into the project's spillway now through Sunday.
An uncontrolled release at the spillway would contribute to increased flow and water elevation downstream of the project.
The reservoir at Arkabutla Lake Dam is currently at an elevation of 235.4 feet and is forecasted to rise to an elevation between 236.0 and 237.0 feet between March 7-10 based on current water on the ground and the National Weather Service's seven-day precipitation forecast. The project's spillway is at an elevation of 238.3 feet; any reservoir elevations above 238.3 feet will pass through the project spillway until the reservoir pool drops back below the spillway crest.
MVK opened the gates at Arkabutla Lake Dam Wednesday to allow for the controlled release of water through the project's outlet works conduit. The gates will remain open providing the water stage at the Coldwater River gage at Marks remains below 39 feet. The controlled release of water from the lake provides for more storage at the reservoir for future rainfall events.
Arkabutla is one of four lakes in Mississippi maintained and operated by MVK. The district's four flood control reservoirs, Enid, Grenada, Sardis and Arkabutla lakes, are used to hold runoff, or excess rainwater, as a flood-prevention measure. During the current flood event, the reservoirs received above average rainfall and each stored an average of nine inches of rainfall runoff. These runoff amounts generated an estimated 320,000 cubic feet per second combined inflow into the reservoirs. The flow at the Yazoo River at Greenwood, Mississippi, which is the collection point for all four reservoirs, peaked at 35,000 cubic feet per second. The reservoirs reduced the peak flow by approximately 90 percent.
MVK will continue to monitor water elevations throughout the region and will issue an update if a change in forecast indicates that spillway flow at Arkabutla is imminent.