Mississippi Sens. Thad Cochran and Roger Wicker are saying the U.S. Environmental Protection Agency does not have the legal authority to veto the controversial, $220 million Yazoo Backwater Project pumping station, as the agency is threatening to do via the Clean Water Act.

The senators submitted a letter to EPA administrator Stephen Johnson Thursday. They said the possible veto – which EPA southeast region administrators recommended last month – raises “serious legal and policy issues.” The EPA’s head office in Washington is expected to give a final decision on the issue this fall, but the senators had requested that Johnson reply to their letter by Friday.

The EPA has, in the past, put the axe to 11 projects using the veto power it was granted in 1979 through Section 404(c) of the Clean Water Act. Earlier this year, the EPA initiated a proceeding to veto the Yazoo Backwater Project pumping station the U.S. Army Corps of Engineers has proposed to construct near the Steele Bayou Control Structure, about 30 miles north of Vicksburg in Issaquena County.

However, Cochran and Wicker contend the agency’s veto power is restricted when it comes to federal projects approved by Congress. The Yazoo Backwater Project was approved by Congress in 1941, and the proposed pumping station is the only unfinished piece of the project.

“We have been telling the EPA this project is exempt from a veto since April or May, and they’ve completely ignored us,” said Peter Nimrod, chief engineer of the Mississippi Levee Board, the local sponsor agency of the Yazoo Backwater Project. “I think they’re obligated to respond to us now that Sens. Cochran and Wicker have stepped up and asked for answers.”

Since being authorized by Congress 67 years ago, the Yazoo Backwater Project has undergone several changes and compromises in its scope and environmental impact. When the Yazoo Backwater Levee was completed in 1978, the 4,093 square miles of land known as the Yazoo Backwater Area became completely surrounded by levees, with the lone drainage point being the Steele Bayou Control Structure.

The gates of the structure are closed when the Mississippi River threatens to cause backwater flooding, at which point the levees designed to protect the Yazoo Backwater Area act like walls of a giant bathtub. Any rain that falls has nowhere to drain. The pumping station would be used to relieve the levee-locked backwater area of flooding when the gates of the Steele Bayou structure are closed and water stages inside the backwater area reach 87 feet above sea level.

During flooding this spring, water stages in the backwater area topped out at 92.2 feet. The Corps estimated a total of 344,000 backwater area acres went under water, 121,000 of them being cleared land for farming. With the pumps in place and working, the Corps contends a total of 141,000 would have been kept dry, including 78,000 acres of farmland.

The EPA and other environmentalists contend the project would have negative effects on the Delta’s wetlands ecology and wildlife, as well as on estuaries further down the river in south Louisiana. EPA Region 4 made a formal recommendation to its head office on June 23 to veto the project. If vetoed, the Yazoo Backwater Project would be the first to be stymied by the EPA through the Clean Water Act since 1990.

Nimrod said Corps representatives and other supporting agencies plan to visit EPA headquarters before Aug. 1 to discuss the project and potential veto.

“This is definitely good news for Delta residents regarding the pumps, which we haven’t had in a while,” said Nimrod. “There’s still a lot of balls in the air. Given the fact that this latest challenge by the senators is a legal one, a lawsuit could easily pop up, but hopefully it won’t come to that.”