SUMMARY OF HYDROLOGIC CONDITIONS
FOR THE
UPPER DELAWARE RIVER BASIN
DECEMBER 1999

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

Adjusted streamflow in the upper Delaware River basin during December was within the normal range. The maximum daily discharge of 6,060 cfs occurred on December 17. The minimum daily discharge was 2,810 cfs on December 13 and 14.

On the basis of a 5-station average, precipitation during December was 1.63 inches, which was 48 percent of the 59-year average. The maximum daily-average precipitation during December was 0.60 inches on December 15. Precipitation in the upper Delaware River Basin during the past 12 months was 1.80 inches less than the long-term average. Precipitation during December was 1.74 inches less than the long-term average for the month. Precipitation has been less than average since Hurricane Floyd in September.

The monthly mean streamflow of the Delaware River at Montague, N.J. during December was 4,109 cfs (observed), which was 83 percent of the median. The flow at Montague, adjusted for diversions from the basin and change in storage in the major reservoirs was 5,789 cfs, or 110 percent of median (water years 1961-90).

Storage January 1, 2000 in Pepacton, Cannonsville and Neversink Reservoirs was 68.6 percent of capacity above the point of maximum depletion. The combined storage of 186 billion gallons was 9 billion gallons greater than that of one month ago and was 87 billion gallons more than that of one year ago. Median storage on the first day of January in 32 years of record is 186 billion 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 December were below average in 6 of the wells. Water levels in most observation wells were trending upward in comparison to November 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 Dec. 1998

January 1999 to December 1999

 

Average

Actual

Percent of average

Excess (+) or deficit (-)

 

Amount

Cumulative

Amount

Cumulative

By month

Cumulative

By month

Cumulative

Jan.

2.97

43.21

5.65

41.41

190

96

+2.68

-1.80

Feb.

2.66

40.24

1.67

35.76

63

89

-.99

-4.48

Mar.

3.30

37.58

4.40

34.09

133

91

+1.10

-3.49

Apr.

3.78

34.28

2.29

29.69

61

87

-1.49

-4.59

May

4.19

30.50

3.32

27.40

79

90

-.87

-3.10

June

3.94

26.31

2.28

24.08

58

92

-1.66

-2.23

July

4.12

22.37

*2.34

21.80

57

97

-1.78

-.57

Aug.

3.87

18.25

3.05

19.46

79

107

-.82

+1.21

Sept.

3.74

14.38

9.08

16.41

243

114

+5.34

+2.03

Oct.

3.40

10.64

2.72

7.33

80

69

-.68

-3.31

Nov.

3.87

7.24

2.98

4.61

77

64

-.89

-2.63

Dec.

3.37

3.37

1.63

1.63

48

48

-1.74

-1.74

 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

1999

Percent of

Maximum

Median

Minimum

Monthly mean

median

(observed)

 18,830 (1996)

4,943

1,968

(1964)

 4,109

83

 December (adjusted)

20,880 (1973)

6,735

2,051

(1946)

 5,789

86

 

 

 

 

 

 

 

January (observed)

15,600 (1996)

4,960

1,318

(1981)

 

 

January (adjusted)

21,330 (1996)

5,874

1,064

(1981)