The U.S. Army Corps of Engineers Memphis District, in partnership with the Fulton County Board of Levee Commissioners (FCBLC), is nearing completion of two maintenance projects, the Island 8 Parcel 1 Relief Well Ditch Restoration Project and the Lake No. 9 Collector Ditch Erosion Repair Project, both located along the Mississippi River Mainline Levee south of Hickman, Kentucky.
Completing these projects is essential, but what's even more important is what comes after.
Once finished, the district will be that much closer to executing the last and final project needed to complete the entire levee system.
This levee system provides significant benefit and protection to portions of two states, $700 million in property and $1.3 billion in agriculture. This final project in question is essential to finishing the overall levee system.
If not, it's like partially patching a hole in your tire. It might work for a little while, but not long. The same goes for this levee system. Without completing the final project, the system will work for a little bit, but not as efficiently or as effectively as it needs to.
Before going too deep into the importance of that final project, let's cover the first two projects at hand, which are both 95 percent complete.
Island 8 Parcel 1 Relief Well Ditch Restoration Project
Following the 2011 flood, the Memphis District installed over 115 relief wells along the Obion River Levee System, beginning approximately five miles below Hickman, Kentucky.
These relief wells significantly reduce the likelihood of a levee breach during high water events. The district completed that project in 2014. The current hired labor work is performing repairs within this reach of relief wells for the Island 8 Parcel 1 Project.
"The Island 8 Parcel 1 relief well ditch system has eroded and degraded over the years, so relief well water is overflowing from ditches at the levee toe and flooding roadways, structures, agriculture land, and infrastructure during Mississippi River high water events," Project Manager Ken Bright said.
Project work for the Island 8 Parcel 1 project includes excavation and placing earthen fill to repair the relief well ditch, re-establishing the ditch design geometry.
Additionally, a gated culvert has been installed in the relief well ditch system to restore proper drainage.
Lake No. 9 Collector Ditch Erosion Repair Project
The second project, Lake No. 9 Collector Ditch Erosion Repair Project, is being executed concurrently with the Island 8 Parcel 1 Project.
"Twenty-one relief wells flow into a field ditch at this site," Bright said. "Concentrated flow during the 2018 flood caused significant erosion to the clay blanket at the levee toe (approximately a 3-foot deep erosion hole at the levee toe extending into the field). This erosion was threatening the integrity of the levee. It caused significant damage to the relief well ditch and the field."
Project work consists of excavating and placing filter material and rock in the relief well ditch at the levee toe to repair and prevent further erosion.
Hired labor crews started work on Mar. 8, 2021. Excavation and rock placement are now complete, with total work being approximately 95 percent complete. Construction completion for this project is scheduled for early April.
"Without the restoration/repairs in these two maintenance projects, local flooding from relief well ditches would continue and could impact relief well performance and levee integrity," Bright added.
The Future and Final Project Needed to Complete Levee System: Island 8 Parcel 2 Seepage Remediation Project
The final project's design, Island 8 Parcel 2 Seepage Remediation, which includes 79 relief wells between Levee Miles 2 and 4, immediately south of Hickman, Kentucky, is ready for execution.
Memphis District members observed underseepage (extensive sand boils) in this reach of levee during the 2011 and 2015/2016 flood events. Sand boils occur because of erosion and piping through the levee's foundation, which can cause the levee to settle and eventually progress to a levee breach if intervention (sandbagging) is not successful.
"The Memphis District is working with its partner, the Fulton County Board of Levee Commissioners, to ready this final multimillion-dollar project for advertisement in the next two weeks," Bright said. "The project was fully funded in the Supplemental Appropriation in 2017 because of the 2015/2016 flood. With our partner's assistance in obtaining the right-of-way for construction, the Corps of Engineers can advertise and award a construction contract later this year."
This project is the last piece of work required to reduce the risk for the entire levee system. It is a top priority for the Mississippi Valley Division and Memphis District.
"Without this final project, the risk associated with the levee system will continue to be considered high," Bright added.
Again, this section of the Mississippi River Levee protects a 487.5 square mile or 312,000-acre area with a population of 15,000 residents in Tennessee and Kentucky, $700 million in property, and $1.3 billion in agriculture.
Project Completion and Future Outlook
Completing these projects is vital as they set the district up to successfully complete the entire levee system, providing significant benefits to this area of the country.
Additionally, the final project will significantly reduce the likelihood of seepage resulting in levee failure during high river events. This future project is federally backed, using the last of the 2017 supplemental project funds to complete this project.
The Memphis District is fully capable and ready to address the critical levee safety concerns in the Fulton County area. We look forward to working with our partners and the local government in that area to make this project a success.