DENHAM SPRINGS — Eden Church Road will continue to flood despite $2.2 million in recent road work unless Livingston Parish spends considerably more on drainage improvements or raising the road’s elevation, an engineer said.
The heavily traveled, 1.3-mile stretch between U.S. 190 and Lockhart Road east of Denham Springs underwent a redesign in 2012 to resurface the road, widen the lanes, bank an S-curve and add turn lanes onto Lockhart. The project was jointly funded by the parish, state and local governments.
After moderate rainfalls led to extensive flooding in December and January, the Parish Council hired a third-party engineering firm, Burk-Kleinpeter of Baton Rouge, to determine whether the project engineers, Alvin Fairburn and Associates, had met state and local design regulations.
Jim Delaune, Burk-Kleinpeter’s vice president, said in a recently released report that despite several drainage problems along the roadway, the Fairburn engineers had met all design requirements.
Neither the Louisiana Department of Transportation and Development nor the parish requires engineers to look beyond a project’s physical boundaries to examine downstream capacity or water levels, he said.
Those downstream conditions, he said, cause much of Eden Church Road’s flooding.
During the project, Delaune said, the road was lowered nearly 3 feet to an elevation 1.7 feet below the bank-tops of nearby Dixon Creek.
New culverts were installed at about the same elevation as the creek, leaving little room to slope drainage away from the roadway, he said.
A drainage lateral carrying water from the road to the creek was mucked out, or cleared, a couple feet deeper to improve outflow. However, even after mucking, the lateral can handle only 30 percent of peak storm water flow from the drainage pipes, Delaune said.
Other downstream pipes with more limited capacity further restrict water flow, he said.
“In effect, what you have is a road that was lowered, that is lower than the creek banks, and that will continue to flood every time the water overflows its banks,” Delaune told the Parish Council on June 13.
Ed Knight, Fairburn’s project manager, said Monday that other limitations associated with the road project also contributed to the outcome.
“Most significantly, that there was no purchase of additional rights of way,” Knight said. “That really makes a difference when you’re designing a curb-and-gutter road.”
Curb and gutter systems, required by a safety grant that helped fund the road work, involve either lowering the road or taking in significant additional space on either side of the roadway, he said.
Acquiring more rights of way would have added to the parish’s costs and may not have been palatable to residents who live along Eden Church Road, Knight said.
Delaune said the parish has two options for fixing the flooding problem: raise the road elevation or improve the laterals and Dixon Creek as far downstream as it takes to get the water out.
“Both of those options are very expensive,” he said.
The design work was adequate for the road project, he said, but not for the downstream drainage effects.
Parish President Layton Ricks said downstream drainage was not within the scope of Fairburn’s work on the project.
“It doesn’t mean that shouldn’t have been done, but it wasn’t part of their work,” Ricks said. “We still need to do something with the creek.”