Pa. Governor Wants to Prevent Seasonal Flooding

Pennsylvania Gov. Edward G. Rendell reiterated his support recently for ongoing efforts to further reduce the risk of future flooding along the Delaware River and called for an additional measure to protect residents and communities throughout the basin.

Since Dec. 13, 1.5 billion of gallons of water—the maximum amount allowed—have been released daily from the reservoirs, creating space to accommodate seasonal precipitation.

Rendell has called for the daily maximum release to continue and has requested that New York City further increase this daily amount to lower reservoir levels.

"I want to assure the residents living within the basin that the river is at normal levels for this time of year and there is no indication or threat of flooding," said Rendell.

Reservoir levels have been reduced from about 99 percent full to about 95 percent full in the last week. The Delaware River Basin Commission predicts levels will continue to drop with maximum releases continuing and cold weather anticipated in the two week forecast.

The three Catskill reservoirs supply drinking water for New York City, ensure drinking supplies to Philadelphia and Bucks County during droughts and protect the Philadelphia Water Supply from salt water intrusion from the Delaware Bay. The Catskill reservoirs began to fill in December as a result of rainy, mild weather.

When the reservoirs reach 100 percent capacity, any additional rainwater flows out the reservoir spillway designed for that purpose. Commission records show that the NYC Delaware Basin Reservoirs spill an average of 111 days per year, primarily in the winter and spring.

On Dec. 13, when the reservoirs exceeded 92 percent of their capacity, the maximum release level safely achievable by existing piping and valves were put into effect as required by the flexible flow management plan approved by the governor in September 2007.

When it is raining, the 1.5 billion gallons that can be released is not enough to keep pace with the rate of filling from runoff. Rendell, through the commission, called upon New York City to take another look at its release works to see whether another way existed to increase releases from the dams.

"Reducing reservoir spills—as a precautionary measure whenever possible without harm to water supply security or fisheries—is just good sense," the governor explained. "Spills through the reservoir spillway are not cause for alarm when the rivers are running near normal, as they are now."

The spill mitigation program in place increases water releases when the reservoirs are nearly full, not because spilling creates an imminent danger, but rather to leave some flood storage capacity in the reservoirs as often as is feasible.

The flow management plan is the first operating plan for these reservoirs that includes flood protection rules, such as counting snowpack as water already in the reservoir, before it melts. In response to the unprecedented devastating flooding in 2004-06, the interim plan was adopted by Rendell and other parties governed by a 1954 U.S. Supreme Court consent decree.

At its December meeting, the commission announced its intention to present a new, proposed flow management plan regulation in June for public review. The proposed regulation would reflect comments received on the current program during 2008, as well as input expected in the next few months on fisheries improvements and flood mitigation opportunities.