Representatives from a group who are promising a lower cost estimate for the dredging of the South Fork Rivanna Reservoir gave a presentation at the December 8, 2008 meeting of the South Fork Reservoir Stewardship Task Force. While their presence was not on the formal agenda, Chair Sally Thomas allowed Mitch King and Mark Fendig of Blue Ridge Sand to speak after the conclusion of the regular meeting.
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Blue Ridge Sand is located in southwest Virginia and maintains two reservoirs behind hydroelectric power plants on the New River. King said that Blue Ridge Sand has the experience in dredging on impounded rivers, as opposed to firms like Gahagan and Bryant whose primary experience is in dredging of coastal waterways. King, who works as a renewable energy commodities dealer, wanted community decision-makers to know that other cost estimates given for dredging are, in his experience, drastically over-inflated.
The company is promoting its amphibious dredge which would simultaneously remove material from the reservoir floor and begin the dewatering process. Sediment would pass through a series of filters, which King said would speed up the process.
“It dewaters in a matter of minutes rather than months and when you do it that way, you avoid the need for a large riparian dewatering facility,” King said. He said the firm is willing to give a demonstration this winter, and that Fendig would know how to get the permits to do so. No permit would be required below a certain level of material removed from the reservoir. Fendig said he could do the limited demonstration for under $20,000.
Fendig said that his equipment would take up less than an acre, and that he has already identified potential sites to dewater the spoils. Sediment would be removed and dewatered at a volume of 100 cubic yards an hour. The material would be sorted and then hauled off to an off-site location which Blue Ridge Sand would manage. Fendig said some of the material could be used elsewhere and that he could sell material for use in the production of asphalt and concrete.
King said that Blue Ridge Sand has taken core samples of the reservoir in 2004 and believe that material on the reservoir floor can be made useful. At time, they were making a formal pitch to the Rivanna Water and Sewer Authority in the wake of the 2002 drought. Fendig said they mostly found sand, gravel and silt but additional geotechnical data on the reservoir’s floor would need to be collected to help his firm know what areas would have more value.
Fendig said dredged material is valuable in southwest Virginia, and that part of the cost of dredging reservoirs there is recovered through selling the material. In fact, he said his company profits off the sale of material. Liz Palmer, a task force member representing the Albemarle County Service Authority, asked Fendig if that meant his firm would offer to dredge the South Fork Rivanna Reservoir at no charge. Fendig said no, but said that the cost of the operation could be reduced if willing buyers could be found.
King said that if the community chose to do a one-time dredge to remove all sediment that has accumulated since the reservoir was built in 1966, there would be a very large cost associated with disposal.
“The cost issue is absolutely related to the rate at which you want the material removed and [if you are] willing to stop removing it if your market dries up for a month or two,” King said.
The task force will finalize its recommendations at a meeting on Thursday in the County Office Building on 5th Street Extended. The meeting begins at 6:00 PM in Room A.
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