Delaware River Flood Study


Michael Mernin, Esq.


Service: Floodplain Management

Delaware River Flood Study

Delaware Water Gap
New York & Pennsylvania

The purpose of this forensic analysis was to determine if there is any flood control storage in three New York reservoirs which might have prevented the loss at an industrial site in Delaware Water Gap, Pennsylvania, during the June 2006 flood. The reservoirs included were Cannonsville, Pepacton, and Neversink. Additionally, modeling of various reservoir management alternatives was conducted to determine the effects on flooding at Delaware Water Gap. To better understand the effects of the reservoirs on flooding, a hydrologic analysis of the entire Upper Delaware River Basin, defined as all areas of the Delaware River which drain into the Delaware Water Gap, approximately 4,155 square miles, was performed. A calibration process was undertaken to match the referenced flows. Based on the results, the maximum flood reduction is achieved at a point when the reservoirs are at 80% of their capacity, effectively reducing, substantially, the normal pool level of each reservoir – approximately 57 billion gallons in water supply storage. With this level of flood control storage, the site at Delaware Water Gap would have experienced a reduction in flood levels during the June 2006 flood of about one foot.