RWSA Study Supports Dredging

A study conducted for the Rivanna Water and Sewer Authority supports dredging the South Fork Rivanna Reservoir, Brandon Shulleeta writes for the Progress. The plan has been to build up the Ragged Mountain Reservoir dam and run a pipeline from South Fork to Ragged Mountain, but that’s going to be awfully expensive. Critics have argued that it’d be cheaper to just dredge the South Fork, and that would provide enough increased capacity for the area’s future needs. The study found that the sediment in the bottom of the reservoir is perfectly safe—that is, not harmful to human health if disturbed. The reservoir originally held 1.6 billion gallons, but it loses ~1% of that capacity annually due to sediment buildup. Dredging it should get it back up to 1.2 billion gallons, which would obviate the need to increase the height of the Ragged Mountain dam or build a pipeline.

10 Responses to “RWSA Study Supports Dredging”

  • The thing about dredging is that, unlike building a dam, it can be done incrementally. That is: if we run out of money halfway through the planned dredging operation, we’ve still increased our capacity. Building a dam, on the other hand, is all-or-nothing.

    Sort of like building a hotel on the downtown mall.

  • You can also sell the sediment as a very good topsoil. You can also do the dredging over and over again. Whereas forcibly taking land away from people is forever. Someone needs to smack down the RWSA board and remind them this is not about creating a legacy for them.

  • build it and they will whine

    I like that dredging is being considered but still think that the 100 year old dam will have to be replaced. I’m not yet convinced it can simply be repaired.

    That said I’ll wait and see what the experts will say about it.

  • Unfortunately this isnt news to the RWSA board. Like the Bush administration with WMDs, they cherry picked data to suggest that we needed this $200 million boondoggle based on faulty population projections (see: biscuit run) and per capita water use projections, while lambasting dredging as a physical and economic impossibility. All in an effort to gain shared ownership of our water resources by Albemarle County.

  • Thankfully Council did what it should have done several years ago. The city owns the dam, not RSWA, and it is the city’s responsiblity to rebuild or modify Ragged Mountain, not RSWA’s. RSWA rents the dam and it is responsible for maintenance. We really need to dismantle RSWA and sell the water to the county as sewer treatment services as we do with UVA.

  • I went to one of the meetings, hosted by Fredricks, a few years ago when they were still tossing around the James River Pipeline (give away to prospective Rt 20 South developers) as one of the options.

    At that meeting it was pointed out by Fredricks that the Ragged Mountain Dam would have to be repaired (and money would have to be spent making those repairs) regardless of what other options/solutions were decided upon. Those repairs were “structural safety repairs” which he said were required by the Federal Government, and raising the Ragged Mountain Dam was an option which would kill two birds with one stone (that last bit of phrasing was mine not his).

    What’s annoying as hell is the amount of money wasted on these do nothing studies, and the water rate increases which were the result of people conserving water to well during the summer droughts.

  • The rates weren’t raised because of consumption. They were raised primarily to set aside funds for future construction (which will allow county residents to become part owners of the new facilities). Currently, there’s $30M in the pot.

  • Citizens for A Sustainable Water Plan will hold a public forum this Sunday, March 14th at 2pm at City Space, on the Downtown Mall:

    “Saving the South Fork Rivanna Reservoir: Dredging For Our Future”

    We will present a detailed analysis; focused on how dredging the SFRR can meet our 50 year water supply needs in a safe, sustainable, and affordable manner for our community. Come with questions and comments-we hope for a lively discussion. For more information about this issue, or to contact us, please visit our web-site

  • There are many misleading and false statements that have appeared over the years about our water plan. Citizens for A Sustainable Water Plan has collected these into the:

    ” Red Herring Report”, to address one question raised here:

    RED HERRING # 29
    *The existing dam can’t be repaired”
    Recent documents report that the existing dam at Ragged Mountain can be repaired and its life extended beyond 100 years. In a memo to the RWSA Board dated 11/24/09, RWSA director Tom Frederick write, “It was suggested in public comment that RWSA staff is saying that the existing Lower Ragged Mountain Dam is “going to fail.” That statement was not true.”

    This red herring arose after RWSA found a letter written in 1913 in which a disgruntled engineer questioned the construction of the existing dam at Ragged Mountain, citing an inadequate spillway and seepage from the concrete dam. RWSA failed to report another letter written a few months earlier in which Wilson Davis writes that:

    “After examining the masonry dam at the New Reservoir I can readily assure you that there is no danger of failure even if filled to the top.” “The Foundation is known to be perfectly solid granite…”

    In 2003 Gannett Fleming did an extensive engineering analysis of the options for repairing the existing Ragged Mountain Dam. The report included geotech analysis of the existing foundation and dam structure and provided a number of alternatives for upgrading the dam. The preferred alternative suggested in the report was to use a roller-compacted concrete buttress to replace the existing earthfill buttress. This solution would extend the life of the dam for another 100 years, at a cost of 3.5 million dollars.”

    At this link you will find the report. Please let us know if you have heard any other red herrings that we could add to this list, or if you find any inaccuracies in our report.

  • RED HERRING # 29
    *The existing dam can’t be repaired”
    Recent documents report that the existing dam at Ragged Mountain can be repaired and its life extended beyond 100 years.

    As I said in my prior post- Fredricks said at our meeting that the Existing Dam had to (as in MUST be) repaired to bring it into accord with federal safety standards.

    And that would cost money.

    Fredricks said that he thought there might be a cost savings by combining the safety repairs (mandatory regardless of the other options taken) with the increase in height/storage capacity.

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