By Sean Tubbs
Charlottesville Tomorrow
Thursday, April 28, 2011

Construction of a new earthen dam at the Ragged Mountain Reservoir could get under way in mid-October, now that the Rivanna Water & Sewer Authority is set to achieve a major milestone in the dam’s development.

Last November, the Virginia Department of Conservation and Recreation ordered the RWSA to submit final plans by the end of April for a solution to address structural issues at the existing Lower Ragged Mountain Dam.

Schnabel Engineering has updated us and they will meet that deadline,” the RWSA’s executive director, Thomas L. Frederick Jr. , said Tuesday.

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Image depicting expanded reservoir (Source: RWSA

In February, Charlottesville and Albemarle County reached consensus on a plan to build a new dam in two phases. The first phase will raise the existing reservoir by 30 feet with a new earthen dam built downstream.

A second phase would raise the dam and the reservoir by an additional 12 feet, but a consensus has not been reached on what conditions would trigger further expansion.

Cost estimates for the construction and design for the first phase of the dam range from $18.3 million to $22.3 million, according to Chris Webster, an engineer with Schnabel.

A request to modify a permit issued by the Department of Environmental Quality in February 2008 has also been made to accommodate for the earthen dam approach. Frederick said the RWSA expects to put the project to bid in the summer and to start construction in the fall.

Despite the compromise, city and county officials still continue to debate whether other components associated with the dam should be phased.

Albemarle County Supervisor Kenneth C. Boyd asked if new trails at the natural area would accommodate a full reservoir rise of 42 feet.

“We don’t want to build them twice,” Boyd said. “I don’t want to have to pay a second time.”

Tom Frederick points out the shoreline of the expanded reservoir

Frederick said that would be up to the Charlottesville Parks and Recreation Department and the Ivy Creek Foundation to determine. The foundation maintains the trails and the natural area surrounding the reservoir.

“They have agreed that [new trails] should be above the 42-foot position but in a few areas where the gap is wide, they may deviate from that slightly,” Frederick said.

However, City Councilor David Brown said he wants replacement trails to fit the site, even if some of them may be inundated if the dam is raised in the future.

The issue also arose when the board discussed a proposal to pay Schnabel Engineering $208,000 to produce a final design for protections to Interstate 64. The western edge of the expanded reservoir will bring the water into direct contact with the highway’s embankment.

Both Boyd and the Albemarle County Service Authority’s executive director, Gary O’Connell , said they wanted the design to take the full height of the reservoir into account.

“It just seems like it is one more thing we have to do when we come back to do the 12 feet,” O’Connell said.

However, Brown pointed out that the council’s insistence on an initial rise of 30 feet was based on a hope that a full expansion of the reservoir would not be required.

“I don’t think this should be treated any differently than how we treat the dam itself,” Brown said. “City Council and a lot of city residents would take issue with saying ‘when’ we come back. I think it’s an ‘if’ question.”

The RWSA board voted to support protections for only a 30-foot pool rise at this time.

However, the board decided Tuesday to implement all of the mitigation steps required for the full reservoir expansion in one phase at a cost of $3.3 million.

That will involve the creation of 4 acres of wetlands in the city’s Woolen Mills neighborhood, as well as tree planting and stream restoration along Buck Mountain Creek in Albemarle.

The next milestone for the dam will be the unveiling of a proposed agreement to determine how the costs for the new dam and other parts of the water supply plan will be split between the city and county. Frederick said he hoped that would be available for public review by May 11.

“We’ve heard loud and clear that the public boards want some time to address this issue and invite public comment,” Frederick said.

However, both O’Connell and the city’s public works director said they would need at least until the end of May before a draft proposal would be ready for the public.

While not directly part of the community water supply plan, the board also voted to pay HDR Engineering just over $18,000 to write a request for proposals for maintenance dredging of the South Fork Rivanna Reservoir. The RFP will come before the RWSA board for review in June before being made available to potential bidders.