Retention Pond Services Inc., a storm water management company, recently completed an extensive pond renovation project on Kiawah Island in South Carolina. In coordination with the Kiawah Island Community Association (KICA) Lakes Management Department, Retention Pond Services removed more than 270,000 cu ft of dirt and sediment from the pond on Turtle Beach Lane, improving its aesthetics and functionality.
“This 2.7-acre pond was one of only several ponds on Kiawah Island maintained at a different water level than the rest of the 115-pond system. It was isolated and had no regular source of water,” said Norm Shea, director of the KICA Lake Management Department, which manages the association’s 115 ponds. “The Turtle Beach pond has proven to be quite demanding over the last 10 years. We relied on rainfall to fill this pond, so if we didn’t have sufficient rain, we had to set up a large transfer pump to fill it from another pond. This was noisy and time-consuming. The renovation project deepened it enough that it could be tied in to the rest of the system, providing it now with a consistent source of water.”
The shallow Turtle Beach pond was created in the late 1980s when a swamp willow-dominated wetland was cleared. By 1991, aquatic vegetation completely dominated the pond from top to bottom. Several costly herbicide treatments were required to remove this vegetative growth, then fish were stocked to keep the vegetation in check. The pond was maintained in this state with supplemental stockings of tilapia and grass carp for nearly 10 years. A prolonged drought in 2000, along with an overgrowth of duckweed in the summer of 2003, resulted in a loss of nearly all the fish.
In 2004, consideration was given to dredge the pond to provide more depth and tie it in with the rest of the pond system. A survey was commissioned to establish the boundary lines, resulting in the pond being classified as a jurisdictional wetland with the U.S. Army Corps of Engineers. This classification required permit approval from the Corps and South Carolina’s Office of Coastal Resource Management in 2005.
“The project was put out to bid in October 2007, and the successful bidder was Retention Pond Services of Wilmington, N.C.," Shea said. "Their level of expertise in quality wetland remediation made them a viable resource for this job.”
Retention Pond Services began work in January of 2008, starting with draining water from the pond and clearing vegetation from the pond’s edge. A Caterpillar 305 amphibious excavator cut the relief ditch to facilitate the draining. The pond was then stacked out and roughly graded. A pair of Caterpillar 324 super-long-reach excavators performed the majority of the sedimentation and dirt removal to increase the depth and water volume. The project took 24 workings days and doubled the capacity of the pond, improving water quality and enhancing the biological diversity.
"We enjoyed working with Mr. Shea and his staff on this unique project," said Retention Pond Services President Glen Garrett. "Kiawah Island has done an excellent job of maintaining their unique ecosystems. We are proud that we were part of the restoration team."
Source: Carolina Newswire
