Posted on January 31, 2017
By Derek Lacey, BlueRidgeNow.com
Sediment flowing into Lake Adger has been a growing problem for years, leading to shallow water levels that at times block access to the lake via the public marina. Dredging operations could soon be underway to start removing thousands of cubic feet of sediment.
Those operations have been in the works for more than a year, but efforts at both the state and county level are being held up by difficulties acquiring property on which to stage the dredging.
The North Carolina Wildlife Resources Commission is working to dredge a channel near its public marina on the western side of the lake, near where the Green River empties into it. Polk County, which owns the lake, is working toward establishing a permanent operation to dredge material out of the Green River before it reaches the lake.
Lake Adger resident Sky Conard has witnessed the piling sediment since she moved to the area, building a home on the lake in 2006. Since then, she has worked to bring awareness and action to the problem. She said she’s relieved and thrilled that wheels are moving to get something done about the sediment.
Kyle Briggs, NCWRC chief deputy director, said the state will dredge an access channel for the marina, but that difficulties in finding land to both dry and store the dredged material mean that the initial deadline — the end of this fiscal year on June 30 — may come and go before the operation is complete.
As part of the agreement made to establish the public access marina around 10 years ago, the state is required to maintain a navigable channel there, something that low water levels are impeding.
The state has been working with Polk County for about a year and a half on this, Briggs said, adding that the Green River watershed is very dynamic, with very erodable soils.
Marche Pittman, Polk County manger, said this effort is nothing new. It’s been an issue at least as long as the four years he’s been county manager, and it’s “absolutely a priority to the county.”
It’s also a concern because some day in the future, Pittman added, the lake will be used as a drinking water reservoir. The more silt that builds up, the less water there will be to access.
The permanent dredging operation in the river needs to be completed first to catch the material before it hits the lake and to extend the life of any other operations conducted at the marina, he said.
Gray Jernigan, southern regional director for MountainTrue, said the environmental advocacy group is involved in the effort at the stakeholder level, working to make sure that any remediation or solution is undertaken in an environmentally responsible way.
Sediment is the No. 1 polluter of local waterways, Jernigan said, a result of naturally sandy soils. It’s exacerbated by development and human activities like agriculture and any type of land-disturbing activity.
Conard said sediment buildup is inevitable in a man-made lake like Lake Adger, which she described as a “catch-all.” The lake was created with the construction of the 85-foot hydroelectric Turner Shoals Dam in 1925.
Sediment has always been present in the lake, Jernigan said, but one of the major impacts has come from the recent removal of the lower dam on the Big Hungry River, which released an estimated 5,000 to 10,000 cubic yards of sediment. This prompted the state Department of Environmental Quality to issue a notice of violation to the NCWRC. A mitigation plan is currently being worked out as a result of that investigation also, he said.
Other contributors include work conducted by PSNC last spring to bury a new gas pipeline under the river about a mile upstream from the lake, and construction work for nearby housing developments.
In 2015, a feasibility report was authored by Asheville-based Altamont Environmental, finding that “Sediment buildup in the western end of the lake severely restricts boat access and recreation usage of the lake.”
According to that report, the west end of the lake, where the public marina is located, is “severely compromised by sediment accumulation.” In that area, water depth is today between six inches and five feet, while historically, the depth was “probably 15 feet or more.”
The study found that dredging the west end of the lake and one mile upstream from the mouth of the Green River to a depth of five feet would cost between $2.55 million and $5.1 million, requiring the removal of approximately 170,000 cubic yards of sediment.
When the Wildlife Resources Commission completes its dredging operation to clear the channel by the public marina, Briggs said it’s likely to remove between 7,000 and 10,000 cubic yards for a navigable channel, depending on the makeup of the sediment, Briggs said.
That material will have to be put somewhere to de-water, and then a location will have to be found to place the spoils permanently.
Briggs said the NCWRC is still trying to identify a site to de-water the significant amount of spoils. If it were to use the parking lot at the public marina, he said, it would likely take up the entire space.
The state-owned Green River Game Lands are a short distance upstream of the lake on the Green River, where the state is focusing its efforts on finding that needed property.
The state also needs a place to permanently put the spoils after they’ve dried, also a possibility for state game lands, Briggs said. There would certainly be areas of public lands where it couldn’t be deposited, though, areas of concern for impacts to things like rare plant species and areas where the sediment would simply seep back into the river.
Pittman said the state has an area it is focusing some attention on within the game lands, a positive since the state won’t have to spend tax dollars buying land. Just how much space is needed would depend on the specific aspects of the dredging operation, and what the land would be used for. If it’s just for the dredging and not for storing spoils, it would likely not take much space, he said.
The main factor is access, he added. Trucks will have to be able to come in to remove the spoils and haul them away.
Briggs said a cost figure is still in the works, and the dredging work will have to go to bid. One of the largest costs will be hauling the material, an aspect that also hinges on the location of a place for the material. The farther it must be hauled, the more expensive it will be.
Once the county acquires the land, work will begin on a plan of just how to dredge the river, and that operation will also be bid out, Pittman said.
Briggs said the NCWRC staff will be in the area this week working on it, and while the Polk County Board of Commissioners hasn’t set a concrete goal for when to have this done, Pittman said his personal goal is to see significant progress within a year’s time.
Source: BlueRidgeNow.com
