RWSA approves dredging study, modified Meadowcreek Interceptor work
By Sean Tubbs
Thursday, October 29, 2009
At their meeting on October 27, 2009, the Board of Directors of the
Rivanna Water and Sewer Authority
(RWSA) approved a contract for a dredging feasibility study of the
South Fork Rivanna Reservoir
, agreed to a modified work order for the
, and directed staff to work with Schnabel Engineering on a proposal to develop a cost estimate for raising the existing dam at
Ragged Mountain Reservoir
by 13 feet.
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RWSA approves dredging feasibility study
After months of discussion between the “four boards”, the RWSA has approved a $343,778 contract with HDR Engineering to perform a series of dredging feasibility studies at the South Fork Rivanna Reservoir. The studies will provide a range of cost estimates for restoring the reservoir to its original capacity and disposing the spoils.
The full study was requested by
in order to determine if dredging would be a cost-effective way of providing some additional water capacity, and Council agreed to pay for studies that dealt directly with dredging for that reason. Members of the
Albemarle County Service Authority
did not feel the information was necessary to move the adopted water supply plan forward, and thus were unwilling to pay for the full suite of studies. Full restorative dredging, and maintenance of that condition over the 50-year period of the community water supply plan, does not by itself provide enough new water storage capacity to meet needs identified in the 2006 plan.
HDR was selected as a finalist for the project in August
, but the price for their services was
initially much higher than City Council had expected
. Earlier this month,
they agreed to a “standard” study that will provide less detail
. Council also removed a study that would have examined the sediment to determine if it had any “beneficial re-use.”
RWSA Executive Director Tom Frederick
RWSA Executive Director Tom Frederick has warned both
and the Albemarle County Board of Supervisors that without the more detailed study, HDR may not be able to come up with a full cost estimate. Another item that was removed by Council was a public meeting that would be held while the study is being conducted so citizens can ask questions of HDR consultants. Gary Fern, who sits on the RWSA Board because of his position as Executive Director of the Albemarle County Service Authority, offered to contribute an additional $8,880 to ensure the second public meeting will be held.
“We’d hate to have all that data and then not be able to express it to the public,” Fern said.
Frederick said a decision on whether to conduct the beneficial reuse study anyway could be made after that meeting. HDR would hold a second public meeting when their study is complete.
One item in the study is a new bathymetric analysis of the reservoir, which will be paid for by the RWSA from its watershed fund. The RWSA will write the check to HDR and will be reimbursed by the City of Charlottesville for the portions of the study that it has requested. The ACSA will pay the $8,880 for the additional public meeting.
According to City Public Works Director Judy Mueller, The City’s share of the study is nearly $256,000 and includes a pre-dredge survey, a characterization of the sediment, an analysis of dredging alternatives, an analysis of potential dewatering sites, and the final public meeting.
The RWSA’s share of the study is nearly $79,000 and includes a bathymetric study, an assessment of whether there are any federally protected wetlands in the reservoir, as well as the final report.
State regulators want answers on dam replacement
RWSA officials have been requested to appear at a November 19 meeting of the Virginia Soil and Water Conservation Board to answer questions about efforts to replace or repair the existing dam at Ragged Mountain Reservoir. A final decision about how to proceed with the dam is not expected to be made until the spring of 2010. That is when Schnabel Engineering, the
firm hired to replace Gannett Fleming in designing the new dam at the reservoir
, is expected to complete its work on a preliminary design and cost estimate.
The Lower Dam at the reservoir is currently operating under a conditional permit from the Department of Conservation and Recreation’s Dam Safety division. The permit expires at end of this month. Frederick said the permit might possibly be extended as long as the RWSA continues to show progress towards complying with state regulations.
Frederick said that the RWSA continues to assume that the Lower Dam will be replaced by a larger one just downstream as called for in the 2006 community water supply plan. However, City Council has also directed Frederick to ask the dam’s new designers to model a scenario in which Lower Dam would be raised by 13 feet. In order to do so, Schnabel will need to perform underwater tests to investigate the strength of the bedrock on which the existing structure rests. Frederick told the RWSA Board that Schnabel’s initial guess was that it would not be cheaper to build on the existing dam because of the complications that could arise when building on 100-year-old technology.
(Samuel Miller) asked if Schnabel would study how the Ragged Mountain Reservoir would be treated during construction. Would the pool have to be lowered, reducing the amount of water available to the community? Would the City and County have to enact mandatory usage restrictions in order to reduce demand? Frederick said he did not have those answers handy, but Schnabel’s proposal for the study will come back before the RWSA Board for a vote at the next meeting in November.
RWSA Chief Engineer Jennifer Whitaker said there are questions about the strength of the dam’s cement core. She also said to build anything on top of the existing dam, construction crews would need to remove an earthen buttress that was built around the dam in the 1930’s to address earlier safety concerns.
“There are legitimate concerns that you could not [remove the buttress] while the water was up against the dam,” Whitaker said. “You’d run the risk of tipping it over.”
Whitaker said before building on top of the dam, Schnabel will need to determine how the existing dam would be incorporated into the new structure, and how the two different types of materials would bond together. She also said a higher pool of water would exert a higher pressure on the base of the dam.
During the public comment period, Richard Lloyd of the group
Citizens for a Sustainable Water Plan
said he thought concerns about the safety of the dam were being exaggerated.
“I don’t get it. That dam is a hundred years old. It has withstood hurricanes, it withstood Camille,” Lloyd said.
Board votes to approve modified work order for Meadowcreek sewer replacement
The RWSA board voted 5-0 with one abstention to place a section of the Meadowcreek sewer interceptor replacement project under the jurisdiction of the Virginia Department of Transportation. Built in the 1950’s by the City and sold to the RWSA in the 1970’s, the Authority is in the final stages of planning a replacement sewer line. Frederick said the existing pipe is deteriorating, a situation made worse after storms when it is infiltrated by runoff.
Part of the pathway for the interceptor lies on the same right of way being used to construct the
. Frederick said in the initial planning for the project, it was assumed the sewer line would be laid before the roadway is built. However, due to a delay over negotiations with property owners in the City for easements to build the interceptor, the road project has moved ahead of the interceptor.
At issue is 410 linear feet on City-owned land in Albemarle County where the RWSA needs an easement in order to proceed, as well as 2,130 linear feet on VDOT property. Faulconer Construction, the company building the Meadowcreek Parkway in the County, has so far delayed their work on this section of land.
Frederick suggested that the Board approve a motion to remove this portion from the rest of the interceptor project so the project as a whole can go to bid. The work on the 2,540 linear feet would be performed by Faulconer as part of their contract with VDOT. However, City Council must approve the easement on its land before the contractor can work on that section of the project. The earliest Council can take up the easements is on November 16, 2009, but they need to have two readings of the matter before it can be passed.
City Councilor Holly Edwards
abstained from the vote because she said had concerns about the design. While on Council, Edwards has consistently voted against the Meadowcreek Parkway.
Thomas asked if Edwards abstention meant that she would not recommend Council approve the easements. Edwards said she would not make that decision until it came time for City Council to vote.
The modified bid will be released on November 5. VDOT will be paid nearly $2 million for the work.
Other news from the meeting:
Frederick asks Board and Council to call on Richmond to appropriate an additional $175 million to the state’s Water Quality Improvement Fund. He said unless the next General Assembly comes up with the funding, the RWSA may receive only two-thirds of the state money it was expecting to upgrade the
Moores Creek Wastewater Treatment plant
. That means the agency may have to find an additional $3.1 million to pay for the project.
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