Emergency plans quietly updated in response to Reservoir issues

The Lewiston Reservoir contains billions of gallons of water. The federal government recently ordered NYPA to update emergency flooding plans in light of possible leaking. The village of Lewiston, the town of Niagara and the Tuscarora Reservation are located next door to the huge, elevated reservoir.


Over 55 years ago, an earthen barrier was built to surround the large reservoir that contains the water supply for the massive Niagara Power Project hydroelectric generating plant at Lewiston, NY. Now it looks like that barrier may be experiencing worrying signs of deterioration, according to government communications recently obtained by the Artvoice.

A letter dated November 27, 2015, from Gerald L. Cross, Regional Engineer for the Federal Energy Regulatory Commission (FERC) division of Dam Safety and Inspections, to New York Power Authority (NYPA) engineer Robert J. Knowlton, reveals that during a June, 2015 annual dam safety inspection, a sinkhole was discovered in near proximity to the Lewiston Reservoir dike.

In response to the FERC write-up, Knowlton, who is based at NYPA headquarters at White Plains, NY, initiated an investigation, and subsequently “indicated that the sinkhole was due to a swale drainage issue and not related to the reservoir.”

“You (Knowlton) have stated that the sinkhole has been repaired and provided photo documentation,” continues the letter. defines swale as “a low place in a tract of land, usually moister and often having ranker vegetation than the adjacent higher land.”

Swales commonly occur on lawns and golf courses, particularly after a heavy rain. A sinkhole, on the other hand, is defined as “a cavity in the ground caused by water erosion and providing a route for surface water to disappear underground.” While Florida is infamous for sinkholes due to erosion of subsurface limestone, a sinkhole at the base of an earthen dam holding back a reservoir may be a sign of a breaching of the embankment and a harbinger of total collapse.

The reclassification to swale, of what was initially identified as a sinkhole by a professional engineer during a formal annual inspection of the base of the Lewiston Reservoir, may be cause for public concern, since FERC goes on to advise Knowlton to “continue to monitor this area… (and if) you note any adverse changes, you are to notify this office immediately.”

History is replete with cases of catastrophic earthen dam failures. Nearby, a 1974 subsurface breach of a bank of the Erie Canal caused widespread flooding of several square miles of a rural area outside Rochester, NY. No lives were lost.

A remarkable YouTube video entitled “Teton Dam Disaster” documents how slipshod planning and construction by the US Bureau of Land Reclamation culminated in gradual erosion of an earthen barrier that held back the Teton River. In the early morning hours of June 5, 1976, a small leak appeared midway down the dam’s face, and four hours later the entire embankment gave way. A large 280 ft. deep reservoir was dumped on farms and towns below. Houses floated away and farms ruined as the flood deluged the Snake River plain, killing 14 people and causing total damages exceeding $2 billion.

There was also the great Johnstown Flood of 1889. 20 million tons of water from a man-made reservoir known as Lake Conemaugh inundated the small city of Johnstown, Pennsylvania, when its earthen dam failed after several days of rainfall, killing 2,209 people.

According to a NYPA Preliminary Draft Environmental Assessment (PDEA) document prepared a decade ago as part of its 50-year relicensing application, “… the 1,900 acre Lewiston Reservoir has a gross storage capacity of 74,250 acre-feet or 24 billion gallons.”

24 billion gallons of water weighs a little over 100 million tons, so the amount of water in the Lewiston Reservoir is approximately five times greater than that involved in the great Johnstown Flood, the worst flooding disaster in US history.

A second letter sent just two months ago from FERC to NYPA, recently obtained by us, clearly indicates that what FERC had persisted in calling a “sinkhole”, caused a good deal of behind-the-scenes activity by the two agencies, activity which only now is coming to light.

In a letter dated June 30, 2016, FERC engineer John Spain wrote to Knowlton, “By letter dated September 16, 2015, you submitted a dam breach analysis that was prepared by your consultant… The analysis was conducted to update the Emergency Action Plan (EAP) and develop inundation mapping… Within 30 days from the date of this letter please provide your plan and schedule to update the EAP.”

To summarize, a suspected sinkhole discovered in June, 2015 was downgraded by NYPA to swale status, but still considered to be significant enough to trigger an update to the Niagara Power Project Emergency Action Plan and formulation of an inundation (“flood”) plan, neither of which was referenced in the original November, 2015 letter.The “inundation plan” referred to in the letters is not available on-line.

The FERC web site responds as follows when one attempts to access the Niagara Power Project Emergency Action Plan: “You don’t have permission to access this document. This document is Critical Energy Infrastructure Information (CEII). The public may file a CEII request under 18 C.F.R. 388.113.”

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Frank Parlato


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  • I have more respect for Bob Knowlton but than your fears but more pertinent is the Shelkopf failure. It occurred in the same rock strata and very famous in the Niagara Falls history. The only loss of life was a Niagara Mohawk employee.
    The designers of the Niagara Project designed the civil works with to prevent this type of failure. The symptoms of the failure at Scheltopf would have scared you but caused me to shutdown the plant.
    The the case of Lewiston I expect any significant failure mechanism increasingly to show up in reservoir leakage.
    The captive pump storage Luddington Reservoir in Michigan owned by Consumers Power has had severed leakage problems.

  • Whenever an engineer tells me with absolute certainty and assurance that a project is 100% reliable and that anyone who raises issues about safety don’t know what they’re talking about and are talking nonsense, I flash back on the Challenger disaster and the collapse of the Embarcadero. Regardless of what the Teton incident led to, it was exactly the kind of failure that a sinkhole at the Lewiston Reservoir could lead to. A professional engineer first identified it as a “sinkhole”, and the first FERC letter persisted in calling it a sinkhole. Then it was called a “swale”. This “by golly and by gosh”, as my father used to say, analysis on the part of the government engineers is concerning, to say the least. The lack of transparency (admittedly for security reasons) surrounding the situation is deeply troubling.

  • Your comment somehow the Johnston Flood of the Grand Teton failure were relevant was totally off base. The Johnson Flood was caused by an event with excessive runoff with sturtures designed in the last century. The Grand Teton failure was unique on because it was during the unitial filling of the reservoir.

    I may be mistaken but the Grand Teton failure, a Federal Bureau of Reclamation lead to current very strict dam dam safety regulations.

    These and many more as many more incidents are studied by engineers and current standard continually upgraded to to improved dam performance.

    For the Lewiston Reservoir except for over topping most events can be prevented without impacting the public. For the overstepping event the emergency action plan is designed to evacuate in effected homeowners.

    I am certain NYPA would welcome your witnessing the next the tabletop exercise. They sent me out to pasture many years ago so they do not keep me informed.

  • Thank you for your comments. Mostly these are facts that everybody knows or has a good idea of. I’m not sure why you felt the need to defend Mr. Knowlton – to my knowledge, he did not perform the inspection and is merely the liaison with FERC. More than likely, the decision to downgrade to a swale was a committee-based decision.
    As far as inundation maps being on file, I received an email from NYPA this afternoon informing me that that information is only for emergency responders. Would you have a comment on that, Mr. Phillips?

  • This is a minor issue.
    Robert J Knowlton is an absolutely unimpeachable Professional Civil Engineer. He is highly respected in the industry. I have worked with him for 25 years on projects all around the State.

    I am a graduate Electrical Engineer with 30 years’ experience in the power industry. In my last 20 years, I was responsible for operations of the Niagara Project.

    The only dike failure of a captive reservoir in the United States was the Taum Sauk reservoir in Missouri. This was due to over pumping. Water in the Lewiston Reservoir has to be pumped up from the Niagara River. It is typically stored at night for use at the Robert Moses Plant the next day. There are elaborate automate interlocks for preventing this from occurring. The reservoir elevation gauge is continuously and visually monitored.

    The reservoir usage is the inverse of the Niagara River flows. Most usage of the Lewiston Plant are highest when river flows are least. This by the way is when capacities of 3000 MW for short periods are possible from the complex.

    All pump storage reservoirs are operated n a weekly cycle in concert with the energy usage times of day. Power demand follows daily and weekly cycles. Maximum demand in on week day peak in the day a less at night and least on weekends. Weekend is when maximum pumpi

  • Kudos to Artvoice for outing this very important issue. The FERC engineers who discovered this defect know the difference between a swale and sinkhole. Swale or sinkhole, it still a very serious matter. Where it it? Is it on the Tuscarora (eastern) side of the Lewsiton Pump Storage Reservoir? The northern side? The western side? Or southern side of the reservoir? Regardless of the side, there are 100’s of residents at risk of catastrophic flood.

    Have FERC and NYPA increased the frequency of inspections? How does one update emergency plans in such instances where a small leak can turn into a raging torrent within an hour or two?

    I’ve been puzzled by the reduced GWh output of the Lewiston Pump Storage facility in the past 2 years. According to the annual NYISO Goldbooks between 2012 and 2015, yearly Lewiston PS output was 509 GWh (2012), 515 GWh (2013), 483 GWh (2014), and 441 GWh (2015). There’s a 14% reduction in power output between 2013 and 2015.

    They refill the reservoir during the weekends as it becomes largely empty by Friday PM. In view of this defect in the dam, perhaps NYPA is not filling the reservoir as much as they used to….a 14% reduction would translate into about a 4 foot reduction in reservoir height (0.14 x 30 feet)…..or perhaps they left the reservoir empty for 50 days of the year (they refill it 183 weekends a year x 0.14 = 25 weekends) as they madly searched for the source of the leak/sinkhole/swale water.

    There could be other reasons for the diminished output. Generator replacement and O&M?

    Aside, I believe the photo above depicts the Sir Adam Beck Reservoir on the Canadian side, not the Lewiston Pump Storage Reservoir, which is out of view off the upper left hand side of the pic. That Canadian reservoir is about 7 years older than the Lewiston Reservoir.

    Again, thanks to James Hufnagle for a great article.