N.Y. City to Adjust Reservoirs to Lessen Delaware River Flooding

New York City has agreed to periodically lower the water level in three of its upstate reservoirs in an attempt to ease flooding along the Delaware River, according to environmental officials.

By leaving the reservoirs below capacity during wet weather, experts believe they could be used to capture far more runoff from a major storm, lessening the severity of flooding in riverbank towns in the Catskills and northeast Pennsylvania.

“It’s not going to stop flooding,” said Clarke Rupert, spokesman for the Delaware River Basin Commission, which oversees the river system. “But our hope is that it will reduce flood losses in the future.”

In the past, the city has tried to keep its Cannonsville, Pepacton and Neversink reservoirs as full as possible during the summer to defend against possible droughts, but that has meant that major deluges spill directly into the Delaware.

The usually placid river, which stretches for 330 miles from the Catskill Mountains to the Delaware Bay, has flooded in each of the last three years, wrecking homes and washing out roads.

A study by the National Weather Service concluded that crests in one damaging 2005 flood could have been reduced by nearly 2 1/2 feet if the water levels in the city’s reservoirs had been lower.

New York’s acquiescence to the plan was first announced last week by Pennsylvania Gov. Ed Rendell.

In the past, New York City’s Department of Environmental Protection, which controls the reservoirs, has been reluctant to tinker too significantly with water supply levels.

Built in the 1950s, the reservoirs weren’t designed to be used for flood control, and there is a danger in draining them too deeply in anticipation of a major storm if the rains then fail to materialize.

Department of Environmental Protection engineer Paul Rush said the city’s water supply wouldn’t be put at risk by the program.

“We have a lot more sophisticated modeling today than we had 20 years ago,” he said.

Nine million people in New York City and its suburbs rely on the reservoirs for drinking water. The reservoirs also are tapped occasionally to ensure that enough fresh water is entering the Delaware to maintain salinity levels closer to its mouth.

Pennsylvania officials said the plan accepted by the city is a temporary one.

New York, New Jersey, Pennsylvania and Delaware plan to spend $500,000 to study reservoir operations throughout the Delaware River basin with the aim of coming up with a better permanent system of mitigating floods.