By Jeanne Sager
TRENTON, NJ — October 17, 2006 — When it rains, it pours – literally.
A resolution passed by the Delaware River Basin Commission (DRBC) just last month will have water pouring out of New York City’s reservoirs into the river basin each time they’re more than 80 percent capacity.
In the wake of three devastating floods in the Delaware watershed in just two years, the governors of New York, New Jersey, Pennsylvania and Delaware pressed the DRBC to act.
A letter signed by all four, dated Sept. 28, said the basin states can act individually to mitigate flooding.
“But we believe that through coordinated effort on a regional basis, we can do more to reduce flood loss within the basin than we could accomplish acting separately, on our own,” the governors said.
As commissioners of the DRBC, the governors called for an interstate task force to develop a mitigation plan that would affect change up and down the basin.
They called for New York City, owners of the reservoirs, and the fifth party in the Supreme Court decree which created the DRBC in 1954, to agree to a temporary spill mitigation program.
According to Clarke Rupert, a spokesman for the DRBC, New York City had the power to veto the entire process.
Instead they opted in, agreeing to release water each time there was an average of 80 percent capacity in the Cannonsville, Pepacton and Neversink reservoirs.
That means the city won’t be taking the 800 million gallons of water from the Delaware River Basin allowed by the Supreme Court decree, Rupert said.
But it also means the city, which depends on the reservoirs to provide 50 percent of its residents’ drinking water, is – for the first time – looking at flood control rather than drought control.
“Up until now, the reservoirs focus has been driven by drought,” Rupert explained.
The reservoirs were kept as full as possible – with water being released only to keep the minimum flow at Port Jervis required by the Supreme Court’s decree.
Since the DRBC was created, Rupert said there have been more droughts than floods.
Flooding is now an obvious problem, he said, and the cold water releases made from the reservoirs since the DRBC was created have formed in-stream habitats and spurred a need to study fisheries in the river.
An interim fishery management plan is scheduled to expire in May, the same time the interim spill mitigation plan will end.
But water has been spilling since the commission passed the program on Sept. 27.
Daily reviews are made of the amount of water in each reservoir – last Friday, they were at 91.8 percent capacity, and water was released.
But Rupert said it’s hard to plan for the weather.
“You can go from a drought to a flood in a day,” he explained. “You can go from a flood to a drought in as little as four months.”
Four months after the April 2005 flood, the DRBC was on the verge of calling a drought warning before it began to rain.
By Memorial Day of that year, just two months after the flood, the city was forced to make releases just to meet the minimum flow target at Port Jervis.
“That’s the real challenge of trying to come up with a real program,” Rupert explained. “No one’s crystal ball is working.”
Coupled with that are challenges inherent in the design of the reservoirs.
“They were NOT designed for flood control purposes,” Rupert said. “If New York City wanted to open the up the valves today to release the maximum, the most they could release would be 2 billion gallons a day.”
By contrast, a flood control reservoir on the Lehigh River that has a tenth of the capacity of the city’s reservoir system could release 6 billion gallons in one day.
During the June flood, there were 90 billion gallons of runoff dumped into the reservoirs.
The valves would have had to have been opened to the max at least 45 days before the flood in order to create a large enough void to capture that runoff, Rupert said.
But in June, the Pepacton and Cannonsville reservoirs were at full capacity when the rains started.
On June 27, the Tuesday when the flooding began in Sullivan County, all three reservoirs were releasing water.
The attenuation effect of the reservoirs did protect properties downstream, Rupert said, because the spill is spread over a longer period of time.
That lowers the peak crest of the river downstream, he explained.
But to have increased the releases beforehand would have required advanced notice of the weather and larger valves.
The cost of changing out the valve system would be “staggering,” Rupert said.
And although the city has considered increasing the size of the reservoirs to create more of a void area for extra stormwater, the DRBC does not have the authority to impose such a mandate on New York City.
“Even though New York City owns the reservoirs, because of the Supreme Court decree, the water is jointly controlled by the parties to the decree,” Rupert explained. “It doesn’t give the commission the authority to unilaterally impose actions on New York City.”
Instead the DRBC is in place to tweak the management of the water.
Most decisions made, however, have to be approved by the commissioners (which includes representatives of the four states, plus a fifth member appointed by the federal government) as well as all five parties to the decree (the four states and New York City).
The DRBC is putting together the interstate task force called for by the governors of the four states, and Rupert said they expect to have a preliminary plan by the end of the year.
The interim program for spill mitigation will expire in May, but the task force will be responsible for suggesting new plans for the five parties to discuss in the future.