Posted on December 5, 2016
By Jason Lesley, Coastal Observer
Dredging at Murrells Inlet began this week, nearly a month behind schedule.
Bubba Young, senior project manager for Gator Dredging of Clearwater, Fla., plans to use both a mechanical press and geo-textile tubes to dry the spoils from the inlet and spend Sundays on maintenance and disposal rather than running seven days a week as originally planned. “That will help us keep up with the dredge material because we don’t have a huge area to stockpile,” Young said. “Everything is being trucked out.”
The dredging company has promised to try and limit noise during church hours since the site is so near Belin Memorial United Methodist Church.
Gator Dredging transformed the boat trailer parking lot at the Murrells Inlet Boat Landing into an industrial site this week with machinery and plastic-lined settling pits and ditches. It began by installing a new culvert under Business 17 for two pipes: one carrying spoils suspended in water and another returning the water to the inlet. Georgetown County Council approved spending $80,000 for the culvert after a business owner worried that the dredge pipes would block the existing culvert and cause flooding.
The culvert will remain as additional stormwater drainage once the dredging is completed, Young said.
Dredge spoils will be piped from the channel to the drying site and into a sand shaker, Young said. “That takes out all the heavies: sand, trash, anything that comes through the pipe.”
He expects the trash to include everything from beer cans to shoes. Next the spoils move to a plastic-lined clarifying pond at the back of the parking lot. The spoils, still in mud form, pass next to a belt press that squeezes out the water. Workers will also use geo-tubes to dry the spoils, Young said, in order to speed up the process and serve as a backup in case of machine breakdowns.
Young plans on having more success with geo-tubes than the company hired to dredge the inlet more than a decade ago. “They had a failure before,” he said. “A bag ruptured. They stacked the bags. They inflate like an oblong water balloon and if not perfectly level they will roll. They stacked them, and one rolled over on to a sharp object, ripped open and created quite a mess.”
Gator Dredging has had success with geo-tubes, he said, removing an invasive plant from Kings Bay near Crystel River, Fla. “Spoils go in as polymerized material; water rises to the top and weeps through the bag,” Young said. “The longer it can sit there the more it dries. When it gets to a manageable loading state, an excavator cuts through the bag and scoops it out.”
The project will begin at the DNR boat landing and proceed to the four main channels leading to the Marsh Walk and Veterans Pier. It will go to Marina Colony Boat Club and end at Marlin Quay Marina. Work must be finished by March 31, according to Larry Setzer of GEL Engineering, hired to represent the county’s interest and see that Gator Dredging follows the contract and the conditions of state and federal permits.
Setzer said GEL Engineering tested sediment and the water that will be returned to the inlet to prove it was not contaminated. Setzer said the geo-tubes would be more of a demonstration project in the beginning. “It’s a test, but at the same time if that helps us keep moving, we may add some more tubes. We are working within a window: the end of March.”
A second phase of the inlet dredging will be conducted by a contractor hired by the Army Corps of Engineers to remove 25,000 cubic yards of sand and sediment from the entrance to the Federal Navigation Channel, inner shoal and the depositional basin at the jetties. That dredge material, found to be 78 percent fine sand, will be placed on Garden City Beach and Huntington Beach State Park.
That dredge is scheduled to arrive Tuesday for assembly. The contractor has called for a safety inspection Dec. 15 and plans to start work that day. The county has received an inspection report from Seismic Surveys, and the contractor has begun to fuse plastic pipe for pumping sand on to Garden City Beach.
Source: Coastal Observer
