Details of new Ragged Mountain earthen dam design discussed at public meeting
By Sean Tubbs
Wednesday, June 2, 2010
answered detailed questions about their
design for an earthen dam
Ragged Mountain Reservoir
during a public meeting Tuesday night.
The event, held by the
Rivanna Water & Sewer Authority
, was the latest in a series of community forums on the evolving community water supply plan.
RWSA Executive Summary
Schnabel Cover Letter
Design – Overall View
Design – Dam sections
Design – Borrow area detail
The design was unveiled in late May by Schnabel, a firm hired to develop a new design after the RWSA rejected a concrete dam proposed by previous consultants
. The cost estimate for the project is between $28.5 million and $36.6 million, according to RWSA executive director
Thomas L. Frederick Jr
One reason Schnabel’s estimate is cheaper is because Schnabel plans to use dirt around the reservoir to build the new dam. Engineer Chris Webster has estimated that at least 850,000 cubic yards of soil is required and that there is at least 1 million cubic yards present.
of the group
Citizens for a Sustainable Water Plan
asked how Schnabel could guarantee there is enough material and wanted to know how much it would cost if there is not.
Project Manager Randall Bass said the answer would not be known for sure until the project proceeds to final design but that the initial cost estimate contained $5 million in contingencies.
“During a preliminary design you don’t think about every nut and bolt,” Bass said. “If you had to import 20,000 yards of clay, you’re talking about half-a-million dollars, well within the limit of the contingency.”
Sam Freilich, a resident of the Ednam Forest neighborhood in Albemarle County, said if a new dam were to be built, he supported going with an earthen dam. However, he said he was alarmed at the size of the dam.
“You’re talking about clear-cutting tens of thousands of mature trees that act as a carbon sink,” Freilich said.
Support for these visualizations comes from our
, the Oakwood Foundation, and the
Virginia Environmental Endowment
Rebecca Quinn, a city resident who served on the committee that selected the firm for a concurrent study of dredging the
South Fork Rivanna Reservoir
, said she did not find anything she could support in Schnabel’s design because she was not convinced its scale was necessary.
“If we don’t have a problem then I don’t care how much the cost is on this dam, it’s more expensive than doing nothing,” Quinn said.
Albemarle County resident Bob Gelges said he liked the project but was disturbed that the opponents of the plan continued to attack every aspect.
“These people have put on two years of additional time and studies,” Gelges said. “We need to get on with this damned thing.”
However, Mooney said she was convinced more than ever that dredging would be a better alternative to building a new dam.
“We’re going to end up saving at least $100 million because our City Council has been brave enough with this dredging study,” Mooney said. The results of that study will be the topic of
another RWSA community meeting on June 30
, when the cost estimate for dredging the South Fork Rivanna Reservoir will be unveiled.
No city councilors were present at Tuesday’s meeting. Three members of the
Albemarle County Board of Supervisors attended