With an abundance of rain expected over the next several days in Albany and surrounding counties, there has been talk of possible flooding. But you may not know that a vast area including Albany already dodged a bullet this weekend.
Some people near it were jarred awake by the boom: an earthquake shook Schoharie County at 11:16 p.m. Saturday, the town of North Blenheim at the epicenter of the 3.0 magnitude temblor. Residents and officials' thoughts immediately turned to the Gilboa Dam.
The Watershed Post reportedthe shaker was felt by people within a 30-mile radius from the epicenter, as far away as Howes Cave in Schoharie County, Roxbury in Delaware County and Durham in Greene County.
Adam Bosch is Director of Public Affairs at the New York City Department of Environmental Protection's Bureau of Water Supply: "We got an email late Saturday night, heading into Sunday from USGS within one minute of the earthquake happening. Our control center alerted some of our operations staff that looked at the information. At first light they went out and did a visual inspection of the dam and found absolutely nothing."
At the same time, New York Power Authority spokesman Steven Gosset says the agency was monitoring several sites including the Blenheim-Gilboa Pumped Storage Power Project. NYPA also automatically receives notifications from the government whenever there is an earthquake within 50 miles of any of its installations. "Upon notification we immediately sent out teams to inspect for any damage. We found none. Next morning we went out, again, to confirm those findings, and indeed there was no damage, and after that we notified the county that as a result of the quake, nothing happened at our facilities, and they continued to operate normally throughout."
Gilboa Dam is 2,024 feet long, 155 feet high, and more than 150 feet wide at its base. It is crucial to the Catskill Water Supply system, one of three surface water systems operated by NYCDEP. It is the northernmost component of New York City’s raw water system, supplying 1.2 billion gallons per day, over 40 percent of the city’s water, to 8 million people.
The worst case scenario, a total breach or collapse of the dam, would, within the course of several hours, swell the Mohawk and eventually the Hudson, flooding riverside communities. Homes along the Hudson River in Cohoes, Watervliet, Colonie and parts of Albany could experience flooding of up to three feet, and hundreds of bridges would likely be closed in case of damage from debris.
The dam was reinforced after Altamont experienced a 2.9 quake in 2011. Saturday's event was closer to the dam — and stronger. Bosch explains DEP had long ago taken steps to ensure the strength and safety of the Gilboa Dam. "You had the floods of 1996. That was the record flood for Gilboa Dam at the time. It was the record flood also for Cannonsville Dam out in the western part of the system. And that triggered a review by DEP of all of its dams, to take a look at 'did they stand up to modern dam safety standards for probable maximum flood' and things like that, and the place we found that needed work, there was a study done in 2002 and some additional analysis in 2005, was Gilboa Dam, which was showing that it may not be able to withstand a storm that was much bigger than the storm in '96, so that's what triggered emergency repairs and a full-scale rehabilitation of Gilboa Dam. It was not a previous earthquake that triggered those things. The emergency repairs were done in 2006. Gilboa Dam was completely reconstructed over a period of years."
The Gilboa Dam Rehabilitation Project came to an end in October 2014. The $138 million dam reconstruction – believed to be the largest public works project in the Catskills – was completed two years ahead of schedule, despite a nine-month setback in the wake of Hurricane Irene, which inflicted historic damage upon the Catskills and the city’s water supply.
Today NYPA and DEP say the dam is sturdier than ever. And people are safe. Again, Steve Gosset: "The 3.0 magnitude quake is considered minimal, it is something that actually occurs on a somewhat regular basis in the Capital Region. In Southern Albany County, in Altamont, there have been similar quakes. They are not known to cause any damage. That doesn't mean that we don't take these events seriously, and we realize that assets like our reservoirs and dams in the area are very important and people will be concerned about them. And we're very dilligent in maintaining their integrity and their safety."
On Monday, the Association of State Dam Safety Officials recognized the Gilboa Dam project as "National Rehabilitation Project of the Year."
