Cooper Lake dam work planned

Cooper Lake (photo by Dion Ogust)

The City of Kingston Water Department plans a $12 million, two-year rehabilitation of the Cooper Lake dam, West dike, water intake and will utilize a temporary connection to the Ashokan Reservoir. Kingston Water Superintendent Judith Hansen and project engineer Greg Daviero from Schnabel Engineering told a roomful of citizens at the Mescal Hornbeck Community Center November 18 why the project is needed. They had already held a similar presentation in Kingston.

Work is expected to begin in April and is necessary because the dam does not comply with current regulations. Further, Cooper Lake lacks an operable low-level outlet which is needed to regulate the lake level. Valves at the West end are no longer operable so the Water Department cannot control the flow of water to the treatment plant on Sawkill Road, which is fed by gravity, Daviero explained.

Officials discovered deficiencies in the dam in 2007 and have worked toward improvements since then. “There are displaced manholes at the toe of the dam,” Daviero said. “The dam had shifted.”

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While it is in no danger of collapse, the dam has to be refurbished.

When work is completed, the dam elevation will increase six feet, but the water level will be the same as it is now. The new height was incorporated into the design to accommodate for more capacity in the future. More work, as part of a future project, will be needed to raise the water level.

Daviero said Cooper Lake is classified as a high-hazard dam, meaning if it were to fail, lives and property would be lost. The classification has nothing to do with the condition of the dam itself, but looks at the consequences of failure. A dam can be in poor condition, but not be a high-hazard dam because failure would not result in loss of lives or property based on where water would discharge, he explained.

Work will include replacement and relocation of intake piping that routes the water through the main that flows down Route 212 and into the treatment plant.

“All the piping goes through the body of the dam. Generally you don’t want pipes going through the body of a dam,” Daviero said.

Water is piped into Cooper Lake near the West Dike from an intake in Mink Hollow. It flows entirely by gravity from the Eastern end of the lake at the dam into a water main down Route 212, then through the Sawkill Road treatment plant to the Binnewater Reservoir.

Mink Hollow via Cooper Lake with its 1.2 billion gallon (one year’s supply, based on current use) capacity is Kingston’s primary water source. The last time the dam was raised was in 1927. Woodstock does not draw water from Cooper Lake, but under the terms of the contract governing the reservoir it retains the right to do so. 

There are documents on file regarding agreements between Kingston and Woodstock, dated 1907 and 1929, but according to Woodstock’s town historian Richard Heppner, writing here in 2014, William Cooper first shook hands on an agreement for water with the City of Kingston in 1894. Heppner wrote “contrary to the belief of some, the whole, early, ‘muddy’ history of how we got to where we are today never really involved ‘agreements’ between the Town of Woodstock and the City of Kingston. Rather, the use of Woodstock water by Kingston evolved through a rather haphazard process of property agreements, condemnations, lawsuits, problems with privies, pipes being laid here and there and a series of access restrictions that, over the years, has left a number of Woodstockers scratching their heads…”

Temporary connection 

To complete the project, the water must be lowered from 1105 feet to 1096 feet above sea level during construction and that height will be maintained through opening and closing of gates at the dike. In case a drought prevents maintenance of an adequate level, a contingency plan will ensure supply.

The plan involves a floating barge with an electric pump to draw water from the Ashokan Reservoir through a pipe that will run under Route 28, next to the shoulder of Zena Road, then onto Sawkill Road and into the treatment plant.

Hansen said likely half the water would be drawn from Cooper Lake and the other half from the Ashokan during a drought.

New York City charges $1800 per million gallons, so that expense is only in the event of a drought.

Neighbors will notice many large trucks

While Hansen and Daviero hope work can start in April, the exact timing of each phase will depend on the contractor that is awarded the bid.

The temporary Ashokan connection, new water supply piping, abandoning the existing piping and the dam and dike improvements are separate phases, though some will be completed quickly and can be done in tandem with others.

One thing that is certain is neighbors will notice lots of construction vehicle traffic.

Daviero estimates a peak of 40 trucks a day for 80 days, averaging five trucks per hour.

In response to traffic and noise concerns, Daviero said he could not provide the route those trucks will take. That will depend on the contractors’ location and the source for the materials. Kingston will have no control over the route or times, but restrictions can be placed in the bid documents. Hansen said she will meet with Woodstock Supervisor Bill McKenna and Highway Superintendent Mike Reynolds to discuss possible ways to minimize truck traffic through town.

One thing that will happen soon is tree removal. This is necessary for work to be done. Additionally, trees should not be growing on the dam or dike structures, Daviero noted.

Hansen said landscaping companies contracted for the work would like to get started before significant snowfall. Tree removal is strongly discouraged between April and October to protect bat habitats.

Who is going to pay for this?

The dam, dike and spillway improvements including the temporary Ashokan connection total $10,660,000. Engineering adds another $1,340,000 for a total of $12 million.

“I’d love to tell you we’re going to pay for it all with grants,” Hansen said. “There really are no grants for dams.”

There is possibly $7 million in grant funding for the Ashokan connection and abandoning of the old water supply piping and the Water Department has applied, Hansen said.

The worst-case scenario, Hansen said, is a $12 million bond over 20 years resulting in a 20 percent rate increase for Kingston users. 

The average Kingston family using 20 units of water per quarter pays $399.04 per year. A 20 percent rate increase is $79.81 for a total of $478.85 per year, according to Hansen.

There is one comment

  1. Eureka Kaplinsky

    Archimedes invented the Archimedian-screw, which raised water from a lower level to a higher level by turning the handle at the top of the mechanism which rotated the hollow thread filling it with water until it was at the desired height.

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