Breaking the Deadlock: Improving Water-Release Policies on the Delaware River Through Operations Research

The Delaware River provides half of New York City's drinking water, is a habitat for wild trout and American shad, and has suffered three major floods in the last five years. The water releases from three New York City dams on the Delaware River's headwaters impact the reliability of the city's water supply, the potential for floods, and the quality of the aquatic habitat. This project's objective was to revise the release policies to benefit river habitat and fisheries without increasing New York City's drought risk. Changes in the release policies were constrained by the dictates of two US Supreme Court Decrees and the need for unanimity among four states and New York City. We describe the analyses and the politics that led the Delaware River Basin Commission to implement our operations-research--based adaptive release framework in October 2007. In addition to meeting our habitat improvement goals and drought-risk constraint, our algorithm conservatively decreases end-of-summer reservoir levels more in wet years, thereby modestly increasing flood protection during the hurricane season, and is substantially simpler to administer.