A new report from Boswell McClave Engineering recommends that the Woodcliff Lake Reservoir dam be kept at a lower level year-round so that it can be raised to alleviate flooding during storms.
Westwood Borough Engineer Stephen Boswell explained the report to officials and concerned residents at a meeting of the Tuesday night. According to Boswell, United Water keeps the dam at its highest level in the summer to maximize its reserves during drought and at a lower level in the winter. If the dam were kept at the lower winter level all year, Boswell said, it could be used during storms to possibly lessen or entirely prevent flooding.
Mayor John Birkner said he hopes the report and the engineering study that it summarizes will allow Westwood to work with other local, county and state officials to push United Water and the Department of Environmental Protection to change dam operations.
"This gives us a tool," Birkner said. "Now we have a basis to back up our argument in support of what the residents have been saying all these years."
However, a representative of United Water, Rich Henning, told Patch Wednesday that the utility is concerned about keeping a sufficient water supply in the event of a drought. Accoridng to Henning, United Water supplies about 800,000 Bergen and Hudson County residents.
"To artificially lower our reservoirs during the summer months, when water is used at its peak, would not be in the best interest of all of our customers," Henning said.
One thing that United Water and local officials agree on is that the reservoir is not the cause of recent flooding. Henning said that many of the affected homes were built on flood plains. Boswell said greater development in the area has contributed to the problems and that it now takes half as much rain to cause the same amount of water runoff as a storm in 1965.
Boswell identified an increase in rain as a main cause of flooding. According to the report, there were only four storms from 1935 to 1999 that reached the local flood stage of 1,500 cubic feet per second, another four from 2000 to 2010 and then another four this year alone.
"Why are you flooding more now? Because it's raining more," Boswell said.
However, before any change in dam operations can occur, Boswell said, United Water will have to set the dam to the lowest possible level for an estimated two years while it undergoes construction. According to Boswell, that means any flood protection the dam has provided will be gone until the work is done.
"If you're looking at a storm which you don't think of as a big storm—where you get two inches of rain in six hours—now you can be protected from that, but you won't be," Boswell said. "But the big ones are still going to be big. That's not going to make a difference."