Panel says Delaware River flooding was unstoppable

Reservoir level reductions before weather events are not a cure FLEMINGTON, N.J. — The Delaware River Basin Commission (DRBC) on Tuesday reported that the last three serious river floods of 2004, 2005, and 2006, would have happened with or without plans to make extra space in upstream reservoirs to reduce their impacts. A new basin flood analysis model demonstrated that widespread river flooding would have occurred in each instance regardless of the storage conditions in the upper basin reservoirs. Other observers have argued that earlier releases from these reservoirs would have cut river volume and lessened downstream damages “The results of the flood analysis computer model... indicate that operational changes to reservoirs alone will not substantially reduce flooding if we experience storms similar to the three major events,” DRBC Executive Director Carol R. Collier said. “... No single approach will eliminate flooding along the Delaware River and... we must continue to focus efforts on implementing a combination of flood loss reduction strategies.” Collier added. Thirteen reservoirs were simulated in the model, eight of which spilled during the floods. The DRBC admitted that, “the model results indicate that larger pre-event voids could have reduced flood crests, but much of the main stem would still have remained in the National Weather Service (NWS) designated moderate or major flood stage.” The agency said that individual characteristics of the storms and local soil conditions and topography also impact the results. A DRBC statement said they “will continue to work with basin reservoir operators to evolve spill mitigation programs that shift spilled water to managed water without diminishing the security of regional water supplies. Eleven million people in New York, New Jersey, and Pennsylvania depend upon NYC’s three Delaware Basin reservoirs for drinking water - either directly via an out-of-basin diversion or through releases to augment river flows downstream. Other actions being pursued include: upgrades of flood warning systems, improving stormwater runoff management, and tighter development measures within the flood plain. The $785,000 flood model was a joint state-federal project begun in 2007 and only recently completed. For more on the project, visit the commission’s web site at www.drbc.net .