Report of the River Master of the Delaware River for the period December 1, 2016–November 30, 2017

Executive Summary

A Decree of the Supreme Court of the United States, entered June 7, 1954 (New Jersey v. New York, 347 U.S. 995), established the position of Delaware River Master within the U.S. Geological Survey. In addition, the Decree authorizes the diversion of water from the Delaware River Basin and requires compensating releases from certain reservoirs owned by New York City be made under the supervision and direction of the River Master. The Decree stipulates that the River Master provide reports to the Court, not less frequently than annually. This report is the 64th annual report of the River Master of the Delaware River. The report covers the 2017 River Master report year, from December 1, 2016, to November 30, 2017.

During the report year, precipitation in the upper Delaware River Basin was 47.85 inches or 108 percent of the long-term average. On December 1, 2016, combined useable storage in the New York City reservoirs in the upper Delaware River Basin was 110.115 billion gallons or 40.7 percent of combined storage capacity, the lowest combined storage of the 2017 report year. The reservoirs were at about 100 percent of useable capacity on May 31, 2017. Combined storage remained above 80 percent of combined capacity until September 2017.

A lower basin drought watch issued by the Delaware River Basin Commission in 2016 extended from the beginning of this report year to January 18, 2017. The drought watch was ended on January 18, 2017, due to increased precipitation in December 2016. River Master operations during the year were conducted as stipulated by the Decree and the Flexible Flow Management Programs.

Diversions from the Delaware River Basin by New York City and New Jersey fully complied with the Decree. Reservoir releases were made as directed by the River Master at rates designed to meet the flow objective for the Delaware River at Montague, New Jersey (N.J.), on 52 days during the report year. Interim Excess Release Quantity and conservation releases, designed to relieve thermal stress and protect the fishery and aquatic habitat in the tailwaters of the reservoirs, were made during the report year. Excess Release Quantity and Interim Excess Release Quantity Bank releases were also made during the report year.

The water quality in the Delaware River estuary between the streamgages at Trenton, N.J., and Reedy Island Jetty, Delaware, was monitored at various locations. The data on water temperature, specific conductance, dissolved oxygen, and pH were collected continuously by electronic instruments at four sites.