Posted on April 25, 2017
By Allison Petty, herald-review.com
Dredging work is underway for the year in two parts of Lake Decatur, with more than half of the $91 million project now complete.
Great Lakes Dredge and Dock, the city’s contractor on the project, started work March 31 in Basin 2 and the Sand Creek area, said Keith Alexander, the city’s director of water management. The crews shut down for the winter each year.
Because Basin 2 includes the Nelson Park shoreline, this part of the work is when boaters are most likely to encounter the dredging equipment that includes booster stations, the large dredge and a significant length of floating dredge pipeline.
No major boating accidents have occurred since the project began in fall 2014, Alexander said, but there have been a few run-ins.
“We’ve had two or three boat owners that did accidentally run into the dredge pipeline,” Alexander said. “So they did suffer some damage either to the beginning of the boat or to the hull.
“Again, all those pipelines are well-marked both day and night. So far, it’s been a very safe project, and we hope it stays that way.”
The project aims to increase the capacity of Lake Decatur by removing tons of sediment from the bottom of the lake and pumping it to a 523-acre storage site in Oakley. Crews work 24 hours a day, 7 days a week.
Alexander said the work remains on track to be completed by the end of 2019. By then, officials have said the lake should have grown to hold 30 percent more capacity, an additional 52 days of water supply.
About 6.3 million cubic yards of material have been removed from the lake, roughly 59 percent of the total goal to remove 10.7 million cubic yards. One cubic yard equals about 200 gallons of material.
Crews are slated to wrap up the dredging of the Sand Creek area this summer, increasing the depth by about six feet in that area, Alexander said. Basin 2 work is slated for completion in the fall, and then the dredge will move north to Basin 3.
The city updates the location of the dredges and booster stations on its website at decaturil.gov.
City officials are also seizing the opportunity during the project to take care of some aging underground infrastructure. Alexander said crews are using the dredge to dig a trench under the lake to replace a water main that runs north of Lost Bridge Road.
“They go down deeper with the dredge to dredge a trench in the lake bottom,” he said. “After that, they will have the water main on their barges, and they will use their barges and their cranes to lower the new water main into the trench.”
The city is increasing the diameter of the water main from 12 to 16 inches to create more water flow for residents on Decatur’s east side, Alexander said. Another water main will be replaced using a similar process in Basin 3. That work was included in the amount of the contract with Great Lakes that the Decatur City Council approved in February 2014, he said.
Source: Herald&Review
