Will the expanded Ragged Mountain Reservoir cause our community to grow too rapidly?
No. Having an adequate future water supply does not cause a community to grow. The objective of water supply planning is to assure that the demand that is reasonably likely to occur in the future will be met. It is not to set growth policies for the community. An inadequate public water supply poses obvious public health risks. Inadequate supply also reduces the amount of water that can be released from dams to the streams to foster healthy and biodiverse aquatic environments. Community growth issues are best addressed with public officials through the processes such as updates to Comprehensive Plans, zoning, and land use regulation.
Do we have enough water?
Technically, yes. But our current use is approaching our capacity; through the first ten months of 2010, our water usage exceeded 80% of our available supply on 101 days.
In addition, given aging infrastructure, it is not clear that our supply of water is both adequate and reliable.
The contractual agreement that formed the Authority in 1972 required that the Authority provide for the future needs of both the City and the County Service Authority. It is therefore an obligation of the Authority to plan ahead, and not wait until there is an emergency or crisis.
The Virginia Dam Safety Office (VaDSO) took a position in the late 1970s that an "unsafe condition" exists with both the Lower and Upper Ragged Mountain Dams that must be remedied. The "unsafe condition" for the Lower Dam is an inadequately sized spillway that would be too small in the event of a major flood, causing the water to flow over the top of the dam, and erode the earthen embankment, which could cause the dam structure to fail. In 2004/5, the Commonwealth began to push for a solution to this problem, and the Authority actively pursued it by developing the Community Water Supply Plan, which has received the permits needed to proceed.
On occasion, the Authority has been criticized for being the "messenger" acting on the Virginia Dam Safety Office’s determination that local action is needed to correct the dams’ "unsafe condition." It has also been suggested by a few citizens that the dam is safe, and the spillway that needs improvement is not a part of the dam. In response, the Virginia Dam Safety Office stated in an e-mail that the "Federal Government . . .and State Regional Engineer have repeatedly stated that the Lower Ragged Mountain Dam is inadequate, with the Federal Government judging the dam seriously inadequate." . This discussion, while sometimes providing valuable public input, has at other times been a potential distraction from keeping our eye on the real ball – that the Commonwealth of Virginia has identified an infrastructure problem, and the Authority is responsible for seeing that it is addressed.
Are we putting all of our "eggs in one basket" by expanding the Ragged Mountain Reservoir?
No. In fact, we would improve our water system’s reliability by expanding the Ragged Mountain Reservoir and building a new pipeline between South Fork and Ragged Mountain. Today, the southern side of the water supply system is limited by the following (click here to view schematic map of water system):
the Sugar Hollow pipeline, which is limited to 4 million gallons per day (built in 1927),
18-inch diameter pipelines, which limit the flow between the Ragged Mountain Reservoir and the Observatory Water Treatment Plant (built in 1908 and 1927), and
an Observatory Water Plant still operating today with 1940s technology.
The Observatory Water Plant is limited to a capacity of 5 to 5.5 million gallons per day because it could not consistently meet today’s drinking water standards if pushed beyond that limit.
Because of these limitations, if the South Fork Reservoir intake or the South Fork Water Treatment Plant had to be shut down for more than a few hours, the water system could not supply the community’s needs, causing an emergency with major shutdown of our water supply.
Under the new Community Water Supply Plan approved in 2006, the water system would be able to meet the community’s needs without interruption if either the South Fork Reservoir or the Ragged Mountain Reservoir had to be closed, even for an extended time period. That’s because the proposed pipeline between these two reservoirs can supply both the Observatory and South Fork Water Treatment Plants with water from either reservoir. By having our largest storage (Ragged Mountain Reservoir) at a separate location from the primary supply (the South Fork Rivanna River), we have actually eliminated our vulnerability to a system failure and improved water supply reliability. In fact, this added reliability and redundancy is the opposite of putting all our "eggs in one basket".
Does the expansion of the Ragged Mountain Reservoir increase the risk of a spill at I-64?
No. In fact, expanding the Ragged Mountain Reservoir would mitigate and reduce the existing risk*. The risk of a spill from a truck on the highway affecting the Ragged Mountain Reservoir water supply has existed since I-64 was built in the 1960s. That is because the interstate highway runs through the watershed that drains directly into the existing reservoir, and because the creek that flows directly into the Reservoir passes through a box culvert underneath the highway fill.
That existing risk will be reduced for a couple of reasons. First, a new spill containment boom will be built across the proposed reservoir (as a part of the new hiking trail system). Second, the South Fork pipeline will provide us with the versatility to remove either of the primary reservoirs from service anytime there is a concern about water quality (click here to view schematic map of water system).
*The actual risk of a spill on I-64 is already very small (estimated at once per 110 years), and has never happened to date. More importantly, the new Project would reduce the risk that such a spill, if it happened, would ever reach our water treatment facilities.
If Schnabel Engineering is predicting that seepage will occur through the new dam, does that mean the dam might eventually fail?
No. In fact, seepage occurs in all dams. Seepage becomes a safety concern only if it is not properly addressed during both design and construction. Qualified dam engineers today have the experience and technology to understand how to manage and control seepage safely; the key is quality design and quality control during construction. Done properly, seepage is controlled to flow much like groundwater moves everyday beneath our homes and the buildings we occupy -- very slowly, safely and naturally, underground.
If the new Ragged Mountain Reservoir were built, would water conservation still be needed?
Absolutely. We will continue to strongly encourage water conservation, particularly practices and choices throughout the community that lead to less water use per capita.
The Community Water Supply Plan is about more than providing water for people; it is also about providing enough water from our local watershed to sustain our rivers, shorelines, and adjacent habitats. Providing the water storage to meet our long-term needs, coupled with smart conservation, would allow us to increase the water level in our rivers, over and above what the law requires. This enables us to be even better stewards of our environment while ensuring the adequacy of our infrastructure into the future.
Some opponents of the Ragged Mountain Reservoir expansion suggest that proponents are opposed to water conservation. Could that be right?
No. That claim mischaracterizes our goals, and those of the broad coalition supporting the Project.
Will the expanded Ragged Mountain Reservoir be a recreational, educational and environmental resource to this community?
Yes. Great care is being taken through design to minimize the impact of construction, keeping it within the boundary of the new reservoir shoreline. We envision the new reservoir as a beautiful lake surrounded by natural forested areas that will provide enjoyment for people and habitat for wildlife.
The County and City Parks and Recreation Departments, working with the Ivy Creek Foundation, will be involved in developing potential uses for the new setting. Possibilities include nature trails, bird watching, nature photography, native plantings, educational and other uses. We remain very receptive to ideas about potential recreation, education, and conservation potentials for the site, and will continue to work with our elected officials, public recreation professionals and community groups to create a broad-based resource.
If you have ideas, please share them with us (info@rivanna.org).
Is there enough clay at the reservoir site to build the core for the new earthen dam?
Yes. The analysis performed by Schnabel Engineering during preliminary design estimated that there would be enough clay on-site to build the proposed core for the new earthen dam. More geotechnical analysis authorized in July 2010 confirms that there is adequate clay on-site.
How long would it take for the new Ragged Mountain Reservoir to fill up after construction?
About two to three years using the existing Sugar Hollow Reservoir and pipeline, based on computer modeling simulation performed by consultants to the Authority. Once full, the reservoir will meet the demand under the condition of every past drought on record even at water demands over 14 mgd. Suggestions that it would take 15 years to initially fill the reservoir are not supported by the data we have available.
How will you assure that the quality of the completed dam is adequate?
We have planned and set aside a budget for qualified inspectors to observe the work and regularly test the materials as they are placed and compacted. This will assure that the contractor is complying with the construction specifications and that the dam and associated structures perform as intended.
Is building a "chimney drain" for an earthen dam unusual?
No. A chimney drain is a vertical channel inside the dam that allows the capture and control of seepage (see discussion of seepage in the Safety and Reliability FAQ, above). Because chimney drains are common components of earthen dams, there is an existing body of knowledge on how to design, construct and maintain them so that they perform well over very long period of time.
Will the South Fork Reservoir and Sugar Hollow Reservoir be abandoned if the Ragged Mountain Reservoir is expanded?
Absolutely not. The approved Community Water Supply Plan calls for continued use of the Sugar Hollow Reservoir as a water supply, but releases the water when needed through the Moormans River to the South Fork Reservoir, instead of releasing it through the 1927 Sugar Hollow pipeline. The Plan also calls for continued use of the South Fork Reservoir and its large watershed as the source for over 95% of the community’s future water.
What are the advantages of the local Community Water Supply Plan approved in 2006?
The Plan provides a clear long-term solution to a long-sought essential and fundamental public health and sustainability requirement of our community.
At the same time, it provides a unique opportunity for aquatic ecosytem enhancement. Using an innovative computer model, and data from a nearby USGS gauging station, we will be able to calibrate and control the release of water to our streams so that it approximates natural streamflow variation, which is important to support aquatic health.
The Plan also provides a large environmental mitigation project to restore and forever protect four acres of wetlands and 14 miles of stream riparian buffer, the largest single project for healthier streams this community has ever undertaken.
In addition, the Community Water Supply Plan is aligned with community efforts regarding water conservation and does not restrict our ability to dredge the South Fork Reservoir.
Isn’t it necessary to perform detailed design of the proposed South Fork to Ragged Mountain pipeline before we build the new Ragged Mountain Dam?
No. Pipelines the size of the one in our Plan, and larger, have been in use for many years, providing a body of knowledge to draw upon. In fact, it is standard practice in the water industry to develop long-range plans at the conceptual level, and then phase the implementation of individual projects within the plan over time. The reason that detailed design on component projects is not performed until near the time a project is scheduled to be constructed, is to make sure that the details on the construction drawings are current and accurate when the project is bid. This practice saves money by reducing the potential for costly claims by a contractor during construction.
Will financing the Dam Project make our water rates "skyrocket?"
No. In fact, the Authority recently performed a financial analysis on its five-year capital improvement program, which includes the full completion of the new dam. Because we started planning for this Project well in advance, we have reserves set aside, and the wholesale rates being charged today are sufficient to finance the construction of the new dam with no rate increase, based on current market conditions.
Is the timing good now to build the dam and expand our Ragged Mountain Reservoir?
Yes, in fact this is an excellent window of opportunity. Recently, Mr. Vince Derr of Faulconer Construction Company was quoted in The Daily Progress (Monday, October 25, 2010) stating: "This is a good climate for the construction customer . . . Prices are very low, and probably as good a bargain as someone could get in the foreseeable future." In fact, if we postpone the Project or delay it by continuing to tweak it and explore unlikely alternatives, we run the risk of losing far more by waiting if prices in the construction market rebound, as we expect them to.
Why don’t we obtain a safe yield of 16.8 mgd by raising the Ragged Mountain Reservoir by only 13 feet and dredging the South Fork Reservoir to its original profile? Would that be less expensive?
No. According to the advice we have received from engineering consultants and our regulatory agencies, it would be significantly more expensive over time. That is because obtaining 16.8 mgd safe yield would require continuously dredging the South Fork Reservoir, over and over, so that its original bottom profile is unchanged 50 years from now. We also know from the Dredging Feasibility Study performed by HDR that dredging the reservoir for the first time costs about the same amount as building the new earthen dam at Ragged Mountain, but provides only 13% of the added water storage provided by the new dam.
According to a letter from the Virginia Department of Environmental Quality to Supervisor Mallek and Mayor Norris, the continuous-dredging and 13-foot dam approach to achieve 16.8 mgd would not meet long-term projected water demand approved in 2004 and would not fully achieve the added flow to the rivers and streams in the 2006 Community Water Supply Plan.
Has maintenance of the South Fork Reservoir been neglected because dredging has not been performed over the past 40 years?
No, it should not be considered neglect. Because dams are designed with additional storage space (called "dead storage") for permanent sediment storage, dredging is a policy choice. Dredging is not required maintenance in the same sense that oil changes are necessary to keep a car running. There are benefits (including water quality and recreation) as well as costs of dredging, leading to a policy choice of deciding if the benefits outweigh the costs.
How much does dredging cost?
Two significant studies have been performed by consulting engineers regarding dredging the South Fork Reservoir. In December 2004, Gannett Fleming published a technical memorandum providing a range of costs for dredging 5.0 million cubic yards of sediment in stages over a 50-year period of time. The final report estimated that range at between $25 and $29 per cubic yard.
In 2009-10, HDR was hired to perform a feasibility study of dredging. After performing a detailed study, including contact with many property owners in the vicinity of the reservoir for potential processing sites, the consultant HDR Inc. provided a plan to dredge 1.1 million cubic yards of sediment presently in the reservoir footprint. That report estimated the cost to beat between $31 and $36 per cubic yard. Those figures did not take into account cost savings associated with sale of sand recovered during dredging, which they estimated to be between 11% and 34% of the total cost. As a result, the all-in, net cost of the HDR study is either $21 - $29 or $25 - $32 per square yard, depending on the sand price estimates used. This means that the two consultants, studying dredging from two different perspectives, and considering changes in construction market conditions over a six year span between 2004 and 2010, estimated the net cost of dredging to be roughly equivalent.
Following the release of HDR’s Dredging Feasibility Study, an incremental approach called "small bites" was suggested by a local citizen. When Mayor Norris asked Mr. Carey Burch of HDR at a City Council meeting if "small bites" would be cheaper, Mr. Burch answered that he believed a "small bites" approach would be more expensive over the long term than the approach recommended in the HDR report.
Can our state and federal permits be amended to call for dredging the South Fork Reservoir and reducing the height of the new dam?
First and foremost, it is important to remember that the state and federal permits were issued based upon findings of law, specifically the federal Clean Water Act and related laws, and it is not a simple matter to obtain an amendment. In fact, the Authority has received advice that amendments to the permits should only be sought in the case of strict necessity, and as minimal as possible given that necessity.
Further, because any amendment to the permit must also be based on law, regulatory agencies can and often will deny an amendment, or amend the permit in ways that are not anticipated, desired, or advantageous. This is true especially when the purpose for filing an amendment is for expedience rather than sound legal findings. It is strongly recommended that the RWSA Board of Directors receive legal advice before deciding to seek an amendment, and carefully consider that advice, before putting the Project’s hard-earned permits at risk.
Do the existing permits prohibit reducing the Ragged Mountain Dam height or dredging the South Fork Reservoir?
No. In the case of reducing the height of the dam in its initial phase, or considering some dredging of the South Fork Reservoir, there are ways that achieve these goals without seeking significant amendments to the existing federal and state permits. With respect to dredging, if the community is able to obtain a credible construction contract to perform some amount of dredging at a reasonable price, separate federal and state permits can be obtained at that time by requiring the contractor to provide them as part of the contract. With respect to phasing the increased reservoir height, the issued permits already provide some flexibility to phase improvements.
In summary, there are much better and safer ways to retain the option to phase the project or to increase dredging, without putting our permits, and their conditions, at risk.
Will expanding the Ragged Mountain Reservoir necessarily lead to the South Fork Reservoir being allowed to "silt in"?
No. The RWSA will still have the option to keep the South Fork Reservoir from silting in by dredging it. The approved Community Water Supply Plan does not place any restrictions on future dredging and RWSA has not opposed dredging. The Plan simply describes the expanded Ragged Mountain Reservoir as the preferred alternative under federal law for insuring long-term adequate future water supply for the community. With an expanded reservoir ensuring the long-term water supply, we can then choose as little or as much dredging as we deem in the community’s interest. We will then be able to take advantage of favorable business conditions and market prices, without being forced to dredge in unfavorable market conditions.
As RWSA personnel recommended during a community meeting in 2005, once the Water Supply Plan is implemented, a separate strategy should be developed for improving the water quality of the South Fork Reservoir, and dredging should be considered. In fact, based on HDR’s 2010 Dredging Feasibility Study, the Authority staff recognized a favorable opportunity addressed in the report and has recommended that dredging sand from the upper part of the South Fork Reservoir be considered for possible implementation based on favorable market and other conditions.
