Dam report considers worst case scenarios

PHILMONT–Two municipally-owned dams in Columbia County are in the “High Hazard” class, according to a report on dams across the state issued by State Comptroller Thomas P. DiNapoli last month.

But don’t panic just yet, the label is misleading.

According to a “Guidance to dam hazard classification” document prepared by the New York State Department of Environmental Conservation (DEC) Division of Water Program Policy: “The hazard class of a dam is an indication of the estimated consequences if the dam were to fail. It is not an indication of the condition of the dam.” So, it’s more about the severity of the damage that could be done downstream if the dam gave way than it is about the shape the dam is in.

A press release about the comptroller’s report says that $360 million is the price tag for the repair of locally-owned dams that are considered a high- or intermediate-hazard to public safety.

The comptroller provides a list of these intermediate- and high-hazard dams in Columbia County as of 2017 based on DEC data at http://wwe1.osc.state.ny.us/localgov/dams/damsbycounty.cfm?county=Columbia.

There are 17 dams on the list, all of them of intermediate hazard, except the last two: the Summit Street Lake Dam in Philmont and the Churchtown Dam in Taghkanic, which are classified as high hazard.

The Churchtown Dam, which is owned by the City of Hudson and holds back the Churchtown Reservoir—a water source for the city—does not have a condition rating. A call to Hudson Mayor Rick Rector about the dam was not returned.

The DEC recently assigned the Summit Street Lake Dam, owned by the Village of Philmont, with a condition rating of “Deficiently Maintained.” This condition rating means that although the DEC recognizes “there is inadequate spillway capacity during a spillway design flood event and the dam will overtop, acceptable performance is expected. At this time there are no existing or potential dam safety deficiencies recognized and acceptable performance of the dam is expected under all applicable loading conditions in accordance with regulatory criteria,” according to email information provided to The Columbia Paper by the DEC.

The Summit Street Lake Dam is on the Agawamuck Creek about 1,000 feet south of State Route 217 along Summit Street.

Reached by phone Wednesday, Philmont Deputy Mayor Douglas Cropper said the village is aware of current issues with the Summit Street Lake Dam, which include deadwood floating on top of the dam and some trees growing on the side of the dam. The Summit Street Lake Dam is 28-feet high and 150-feet long with a surface area of 16 acres and a normal water capacity of 178 acre/feet, which is 58,001,554.29 gallons, according to an online conversion application.

Mr. Cropper said the issues with the dam are “not extreme” and the village engineer examines the dam every four or five years to see if there are any structural concerns. He said once the water level goes down, the wood will be removed from the top of the dam.

Mr. Cropper said in the event that the dam should fail the Village of Philmont would not be substantially affected. He said based on flood plain maps, the water would flow through the gorge over High Falls and impact the Hamlet of Mellenville.

He said the dam failure that would have the most impact on the village is Philmont Reservoir Dam, privately owned in Claverack, on the other side of the Taconic State Parkway. On the comptroller’s list, that dam is classified an intermediate hazard and has no condition rating.

Mr. Cropper said the Philmont Reservoir Dam is an earthen dam created as “an extra water source” to run the mills back in the days when the mills were operating.

Both the Churchtown Dam and the Summit Street Lake Dam have Emergency Action Plans (EAP) on file with the DEC.

Columbia County Emergency Management Office Director David Harrison, Jr., told The Columbia Paper that the hazard classification is about “what would happen if a dam were to fail, not that failure is imminent.”

Appointed in May to fill the position vacated by Bill Black, who retired, the former Sheriff Harrison said local emergency services such as fire companies, law enforcement agencies, rescue squads and city, town or village officials are the first line of defense and are the people who would respond or act should the need for evacuation or other emergency arise.

Mr. Harrison said his office would assist them by bringing in county or state resources if necessary.

The Summit Street Lake Dam EAP, which is also part of the Village of Philmont Comprehensive Emergency Management Plan, establishes “procedures necessary to protect life and property in the areas affected by the failure of the Summit Street Lake Dam or the uncontrolled release of stored water from the lake.” It calls for the notification of certain agencies in a specified order based on the level of the emergency condition identified. Conditions include everything from an unusual situation or problem with no failure expected to imminent failure or failure that has occurred leaving no time to attempt corrective measures to prevent failure.

According the EAP, an Emergency Operations Center would be located at the Village Hall and Michael Scheller, the Village superintendent of public works, would serve as the EAP coordinator.

A “surveillance checklist for enhanced monitoring during an emergency,” report forms, a list of contractors, available equipment and materials on- and off-site, inundation maps and training for implementation of the plan are all contained in the EAP.

In the dam report, Comptroller DiNapoli recommends that local officials:

Ensure emergency action plans and annual certifications are adequate and up to date, and take prompt action to address deficiencies identified by inspections and engineering assessments

Include dams in capital asset planning and establish long-term financial forecasts for dam maintenance and, if necessary, rehabilitation

Raise awareness about dams that could affect residents. In addition to their own dams, local officials also need to know about other intermediate- and high-hazard dams that could affect their residents and businesses.

To read the report “Dam Infrastructure: Understanding and Managing the Risks,” go to: http://www.osc.state.ny.us/localgov/pubs/research/dam-infrastucture-2018.pdf

To contact Diane Valden email moc.r1542554745epapa1542554745ibmul1542554745oc@ne1542554745dlavd1542554745

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