SUMMARY OF HYDROLOGIC CONDITIONS
FOR THE
UPPER DELAWARE RIVER BASIN
May 2000


Prepared by the
Office of the Delaware River Master
Milford, Pennsylvania

 

Adjusted streamflow in the upper Delaware River basin during May was excessive. The maximum daily discharge of 27,900 cfs occurred on May 25. The minimum daily discharge was 3,840 cfs on May 7. 

On the basis of a 5-station average, precipitation during May was 5.76 inches, which was 138 percent of the 59-year average. The maximum daily-average precipitation during May was 0.82 inches on May 24. Precipitation in the upper Delaware River Basin during the past 12 months was 1.48 inches greater than the long-term average. Precipitation during May was 1.59 inches more than the long-term average for the month. 

The monthly mean streamflow of the Delaware River at Montague, N.J. during May was 10,570 cfs (observed), which was 151 percent of the median. The flow at Montague, adjusted for diversions from the basin and change in storage in the major reservoirs was 11,690 cfs, or 142 percent of median (water years 1961-90).

Storage June 1, 2000, in Pepacton, Cannonsville and Neversink Reservoirs was 100.8 percent of capacity above the point of maximum depletion. The combined storage of 273 billion gallons was 1.7 billion gallons greater than that of one month ago and was 22 billion gallons more than that of one year ago. Median storage on the first day of June in 33 years of record is 269 billion gallons. Cannonsville Reservoir spilled continuously throughout the month and spilled more than 26 billion gallons. Pepacton Reservoir spilled all days except May 9 and spilled nearly 13 billion gallons. Neversink Reservoir spilled from May 24 to May 28 and spilled 160 million gallons.

As part of a statewide network, the USGS operates 14 observation wells in the Pennsylvania part of the Delaware River Basin. Mean water levels during May were above average in 7 of the wells. Water levels in 12 of the wells were trending downward in comparison to April levels. Water levels in all 14 wells were above the May 1999 levels.

 

 

HYDROLOGIC CONDITIONS IN THE UPPER DELAWARE RIVER BASIN
Compiled by the Office of the Delaware River Master, Milford, Pa.
(Preliminary data - subject to revision)
PRECIPITATION, IN INCHES

 

 

 

Dec. 1940 to May 1999

June 1999 to May 2000

Average

Actual

Percent of average

Excess (+) or deficit (-)

Amount

Cumulative

Amount

Cumulative

By month

Cumulative

By month

Cumulative

June

 3.94 43.22 2.28 44.70 58 103 -1.66 +1.48
July 4.12 39.28 2.34 42.42 57 108 -1.78 +3.14
Aug. 3.87 35.16 3.00 40.08 78 114 -.87 +4.92
Sept. 3.74 31.29 9.11 37.08 244 119 +5.37 +5.79
Oct. 3.40 27.55 2.72 27.97 80 102 -.68 +.42
Nov. 3.87 24.15 2.75 25.25 71 105 -1.12 +1.10
Dec. 3.37 20.28 *1.84 22.50 55 111 -1.53 +2.22
Jan. 3.02 16.91 3.22 20.66 107 122 +.20 +3.75
Feb. 2.64 13.89 3.07 17.44 116 126 +.43 +3.55
Mar. 3.32 11.25 3.98 14.37 120 128 +.66 +3.12
Apr. 3.76 7.93 4.63 10.39 123 131 +.87 +2.46
May 4.17 4.17 5.76 5.76 138 138 +1.59 +1.59

Note: Amount shown in cumulative columns is total from month shown to present.

* Revised since previous month

 

STREAMFLOW, IN CFS

DELAWARE RIVER AT MONTAGUE, N.J.

Month

1940-98

2000
Monthly mean

Percent of
median

Maximum

Median

Minimum
May (observed 16,090 (1943) 7,019 2,215 (1965) 10,570 151
May (adjusted) 18,970 (1989) 8,256 2,944 (1941) 11,690 142
               
June (observed) 15,200 (1972) 3,199 1,214 (1965)    
June (adjusted) 16,010 (1972) 3,948 1,024 (1962)