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Report of the River Master of the Delaware River for the period December 1, 1986-November 30, 1987, with a section on water quality

1988; United States Department of the Interior; Linguagem: Inglês

10.3133/ofr88462

2332-4899

Stanley P. Sauer, William Harkness, Bruce E. Krejmas, K.E. White,

Soil and Water Nutrient Dynamics

Precipitation in the upper Delaware River basin during the 1987 River Master report year varied from 15 percent of the long-term average during February to 193 percent during September (See table 1).Total precipitation during the year was about 0.5 inches above average.Heavy precipitation (134 percent of average) occurred primarily as snow during January and resulted in fairly heavy snow cover over much of the upper basin.A snow survey during the first week of February indicated an average of 3.2 inches equivalent above Cannonsville Reservoir, 3.6 inches above Pepacton and 5.4 inches above Neversink.Storage in the reservoirs at that time was 85 percent of capacity, Cannonsville was already spilling, and the potential existed for very high runoff during the spring thaw.However, precipitation during February and March was very low and melting proceeded slowly, thus reducing flood potential downstream.Most of the snow pack melted prior to any significant precipitation.The peak discharge at Montague was 65,200 cfs on April 5, 1987.This peak had approximately a 2-year recurrance interval and occurred as the result of rainfall averaging about 3.3 inches during the previous week.On December 1, 1986, when the report year began, combined storage in the New York City reservoirs in the upper Delaware River basin was 225 billion gallons, 83 percent of capacity.All reservoirs filled to capacity during the winter and spring.Cannonsville began spilling on December 6 and spilled continuously until April 28 except for a brief period, February 24 to March 2, when the storage was within 0.8 ft. of spillway level.A total of 68.7 billion gallons spilled in addition to the augmented conservation releases and a few small directed releases during February.Pepacton reservoir filled to capacity on April 7, and spilled a total of 13.2 billion gallons from April 7-24.Neversink Reservoir filled on April 6 and spilled a total of 8.3 billion gallons April 6 to May 5.The reservoirs reached a maximum combined storage of 278.160 billion gallons, 102.7 percent of capacity on April 8, 1987.On June 1, 1987, the start of the water operations year, storage was 250.826 billion gallons, 92.6 percent of capacity.Median storage for June 1st is 270.194 billion gallons, 99.8 percent.The minimum combined storage during the year was 174.060 billion gallons, 64.3 percent of capacity on September 8, 1987.Throughout the year, diversions for water supply for New York City and releases designed to maintain the flow of the Delaware River at Montague were made as directed by this office and as provided in the Decree.Diversions by New York City from the Delaware River basin reservoirs did not exceed the limit specified by the Decree.Orange and Rockland Utilities, Inc. brought the Rio powerplant back on line in mid-February.The plant had not been used since the penstock collapsed in 1979.Records of forecast and actual releases used by this office for the Mongaup system are for Mongaup reservoir December 1 to February 25 and Rio reservoir February 26 to November 30.During the report year, the River Master and staff participated in meetings of the Delaware River Basin Commission to assess water-supply conditions.Upon invitation of the representatives of parties to the Decree, the Deputy River Master met periodically with those representatives as a member of the Flow Management Technical Advisory Committee.Discussions primarily centered on proposals for the management of releases from reservoirs in the basin and other measures designed to cope with streamflow deficiences whenever they occur.