New Jersey v. New York

Background

The State of New Jersey sued to stop New York and the City of New York from diverting water from the Delaware River and several of its headwater streams (including the Neversink, Willowemoc, Beaver Kill, East Branch and Little Delaware) to supply New York City. Pennsylvania intervened to protect its future needs. The dispute was referred to a Master, who collected extensive evidence and evaluated how much water New York could take without materially harming downstream states.

Reasoning

The Court accepted the Master’s reliance on equitable apportionment between States rather than strict private riparian rules. The Master found that the full plan to take about 600 million gallons daily would unduly burden New Jersey, but that a reduced diversion of 440 million gallons daily could be allowed if strict safeguards were imposed. The Court confirmed the Master’s report, concluding the proposed diversion (as limited) was reasonably necessary, would not seriously harm navigation as presently judged by Army engineers, and should proceed subject to sanitation, flow-restoration, inspection, and other conditions.

Real world impact

The decree lets New York and New York City divert up to 440 million gallons daily, but bars larger diversions. It requires a Port Jervis sewage-treatment plant with specific impurity and bacterial reductions, limits industrial discharges, mandates releases from reservoirs when river flow falls below defined levels, and gives New Jersey and Pennsylvania inspection rights. The decree preserves congressional authority over navigation and may be modified later by the Court or affected federal agencies.