No snowpack? Not to worry (yet)
SNOWPACK: A MASS of snow on the ground that is hardened by its own weight. (Thanks, Google)
Snowpack is important for the Delaware River because the water from that snowpack can ease out of its frozen state and help to fill the reservoirs when rainfall is low, which it can be in March and April.
This year, there's no snowpack in the watershed for the New York City reservoirs and much of the water in the Delaware River comes through the Cannonsville, Pepacton and Neversink reservoirs.
Does no snowpack spell trouble ahead for New York City's water supply, and for the millions of people who rely on its waters downstream?
Apparently not. At least according to Adam Bosch, the Director of Public Affairs for the Bureau of Water Supply, New York City's Department of Environmental Protection.
"It's been simultaneously a bizarre year and a normal year," he said.
Yes, Bosch said: "The amount of snowpack is zero." But despite that, the reservoirs are quite full. As of Thursday, Feb.25:
Current Storage %: 92.9
Normal Storage %: 87.1
And five percent over normal is billions of gallons. Last year the total was well below average, with some reservoirs half full or less.
"Even though we don't have snow," said Bosch, "everything we rely on is showing we're in good shape … and that's principally because the the rains have been frequent through the winter, and they've been spread across the whole watershed." When the rains are widespread throughout the reservoir watershed, it means all the reservoirs can be full and ready for a dry spring.
The Delaware River Basin Commission, whose main purpose is to insure there's enough water for all four states that depend on it, is also not too concerned about the snowpack. This is its statement:
DRBC staff and their respective agency counterparts regularly monitor snowpack levels, precipitation frequency, stream flows, the salt front, and reservoir storage in the Delaware River Basin. At this time, there is some concern with the current snowpack levels in the basin. While very little, if any, snowpack remains in the basin, reservoir storage is at or above storage median levels, and streamflows are generally normal or above normal. As of February 22, 2016, the combined storage in the NYC reservoirs is 235.8 BG (87.1% of capacity), which is 7.8 BG above the daily storage median. In the Lower Basin, Beltzville and Blue Marsh reservoirs are at 100% and 102% usable storage capacity, respectively.
While the lack of snowpack is a bit unusual for this time of year, there is still plenty of winter left. A close watch will be kept on hydrologic, reservoir, and river conditions as we move forward into spring and summer.
Ben Gelber, a meteorologist now based in Ohio who works for NBC4 in Columbus, has remained interested in the weather systems in the Delaware River from growing up in Stroudsburg, Pa. and attending Penn State. He analyzed this winter's weather from the perspective of the El Niño effect. But before he did, he stressed that you can learn from models in the past, but there's no one thing that creates weather.
"No two El Niños are the same, but both the winters of 1982-83 and the one of 1997-98 are similar to this year. Both were light on snowfall," he explained.
So far this winter it's been dry, but he noted "We took care of that yesterday," referring to the wet midweek Feb. 23/24. With about 2-3 inches of rain falling in the watershed, the numbers are up. As he put it, "It was a good deposit in the water bank."
Looking forward, he expects that even as the El Niño effect fades, it will still give us a drier than usual last half of winter, but that could be balanced with a wet spring.
Clearly weather creates hard calls, and the water supply system is volatile as a result. Last year, the reservoirs were really low going into June. Then there were consistent heavy rains, that filled reservoirs across the whole system, not just the Catskill/Delaware reservoirs.
"And that was such a blessing when we had that problem (see note below) in Cannonsville," Bosch said.
That problem in Cannonsville
In July there was a change in the color of the water discharged below the Cannonsville dam. Dirty water can mean a leak in the dam. The alarm was sounded in case there would be a dam failure. At the same time water was released at the fastest, safest rate from the dam. That was only possible because all the other reservoirs in the system were filled just about to capacity. Releasing water posed no threat to New York City's water supply.
"People misconstrued (the ability to release water) as 'you don't need that water.' If we hadn't had those late rains," said Bosch,"we wouldn't have been able to release the water we did."