The Charleston District has simultaneously been working with three municipalities to restore three creeks that were damaged by intense rainfall from Hurricane Joaquin in 2015.
In 2015, the District conducted post-storm inspections with the Town of Summerville, Town of Kingstree and Sumter County to evaluate the impact of the storm and damage to Sawmill Branch, Kingstree Branch, and Turkey Creek.
Each creek is a federal flood risk management channel that was originally built by the Army Corps of Engineers and is maintained by the municipality who serves as the project sponsor. During the storm, each creek had major inflows with the existing channel struggling to move all the water and led to flooding beyond its banks. The amount of flooding led to significant damage, causing additional concern during hurricane season and future rainfall events.
“Each channel is designed to accommodate a specific intensity storm event, such as a 25-year storm, but not larger intensity storms such as a 100-year storm,” said Nova Robbins, project manager. “In order to perform as designed, it is important that the channel be maintained properly, and any damage be repaired so that it can handle rainfall and move water efficiently.”
Each year, the District inspects these creeks to ensure they can perform as designed and establish a baseline condition. If it is determined a declared-disaster caused damage, the projects become eligible for federal flood control and coastal emergencies funding to make the repairs.
This became the case after Hurricane Joaquin in 2015, when a large storm system drew in moisture from the hurricane and flooded much of South Carolina to historic levels. When these creeks were overtopped, the towns had significant flooding issues.
The flooding of the creeks also eroded the banks on each side, causing more problems. Now, the banks were collapsing and reducing the performance of the channel.
After the storm, the District received $2.2 million in federal funding to restore the creeks back to their pre-storm conditions. Sections of the creeks that were most impacted are being restored and having their banks re-graded. In Kingstree Branch, the crew is installing gabion baskets to hold up the banks.
Gabion baskets are large wire baskets filled with rocks and secured into the ground. This allows for a more vertical bank and makes the earth behind it less likely to be washed away because it has a solid structure supporting it.
The District has completed the work at Sawmill Branch and is currently working on Turkey Creek and Kingstree Branch. All work is anticipated to be complete in late Summer 2020.
This work is somewhat irregular for the District, taking place this far inland from the coast. As one the Corps’ primary missions, the District oversees numerous flood risk management projects throughout the state. Soon, the creeks should be restored, improving protection for the citizens of these communities.