Consultants hired by the Rivanna Water & Sewer Authority presented the final results of its dredging feasibility study at a public input session attended by about 40 people Wednesday evening.

While numerous community members expressed appreciation for the consultants’ analysis, speakers quickly got into a debate with Thomas L. Frederick Jr., RWSA’s executive director, on dredging approaches and the merits of many elements of the community’s long-term water supply plan.

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City resident Rebecca Quinn, one of Charlottesville’s citizen representatives on the dredging firm selection committee

Rebecca Quinn, one of Charlottesville’s citizen representatives on the dredging firm selection committee, said she was very pleased with the work of HDR Engineering .

“Considering the breadth of what they were asked to do, I thought they did a masterful job,” Quinn said in an interview. “I thought they were thorough and clear and thoroughly addressed the scope [of work] as requested.”

Carey Burch, the HDR project manager, made a presentation on the costs and feasibility of dredging the South Fork Rivanna Reservoir. HDR is recommending a multi-phase, one-time dredging project that would cost $34 million to $40 million and take about seven years.

“It is a two-part approach. In part one, we recommend hydraulic dredging in the upper three segments of the reservoir,” Burch said. “The upper three sections is where most of the sand is and represents most of the material that has recovery value.”

HDR identified 1.4 million cubic yards of total material that it said could be realistically removed in the two phases of a dredging project. Burch said some materials removed from the reservoir, such as sand, could be sold potentially in the local market and thereby reduce dredging costs by $5 million to $9.5 million.

Thomas L. Frederick Jr., RWSA’s executive director

Frederick said the RWSA is only recommending pursuing the first phase of dredging, for sand recovery and sale, but not as an alternative to the water supply plan. However, he said the first phase of dredging would provide only 59 million gallons of new water storage capacity, as compared with 1,726 million gallons from a new reservoir.

Frederick said on a cost-per-cubic-yard basis, a new dam at Ragged Mountain would provide greater water storage at a much lower price. His assessment, however, was quickly challenged by opponents of the community water supply plan who favor dredging.

“What I hear is a lot of bobbing and weaving to avoid answering a question directly,” former City Councilor Kevin Lynch said. “What we are getting is a lot of non-answers.”

The studies and debate have been ongoing since local elected officials signed off on a water supply plan in 2006 that is intended to meet water needs for the next 50 years. The original plan, which did not include dredging, would construct a higher dam at Ragged Mountain Reservoir and build a new pipeline to transfer water from South Fork Rivanna Reservoir to Ragged Mountain.

John Martin, a board member of the Albemarle County Service Authority , said after he reviewed HDR’s dredging report that he still couldn’t support dredging for water supply needs.

“It won’t provide enough water,” Martin said in an interview. “We should go ahead and build the approved water supply plan.”

Neil Williamson, who represents local businesses as executive director of the Free Enterprise Forum , said the community must keep in mind HDR’s proposal was for a one-time dredging.

“The costs that have been released in the HDR study do not include maintenance dredging and as such fails to recognize the long-term costs of dredging as a water-supply solution,” Williamson said in an interview.

Tom Olivier, Piedmont Group of the Sierra Club

Tom Olivier, representing the Piedmont Group of the Sierra Club , thanked the presenters for the information on dredging.

“The position of the Sierra Club has been that better information was needed on several fronts and the dredging study provides part of what we need,” Olivier said. “We are still awaiting for the new [water supply] demand analysis, one that includes conservation efforts in the community.”

“When you get into things like the water plan … the demand figures were based on projections of a linear increase in water demand over the next 50 years,” Olivier said in an interview. “The question is, ‘Is that sustainable?’ Maybe we will decide before we reach this linear 50-year projection to try to stabilize our population at a somewhat lower level.”

The dredging feasibility study cost about $369,000. Charlottesville taxpayers will pay for $281,000 of that amount, as the Charlottesville City Council requested the study. The remaining costs are being split between the city and the ACSA.

Quinn said she thought the city got a good return on its investment and echoed Olivier’s call for a new demand analysis.

“I think we do have a good estimate [of the costs of dredging],” Quinn said. “I think we now have what we need to factor dredging into the decision process. In my opinion, the next key step is really the demand analysis.”

After the meeting, Frederick said he thought the next time the RWSA board would discuss dredging would be at a yet to be scheduled “four boards” meeting in late summer. The Albemarle County Board of Supervisors, Charlottesville City Council, RWSA and ACSA boards are expected to gather then to make decisions about the next steps for the water plan.