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


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

Adjusted streamflow in the upper Delaware River basin during September was excessive for the fifth consecutive month. The maximum daily discharge of 6,240 cfs occurred on September 14. The minimum daily discharge was 1,850 cfs on September 24. 

On the basis of a multi-station average, precipitation during September was 3.53 inches, which was 92 percent of the 59-year average. The maximum daily-average precipitation during September was 1.46 inches on September 13. Precipitation in the upper Delaware River Basin during the past 12 months was 3.46 inches greater than the long-term average. Precipitation during September was 0.30 inches less than the long-term average for the month. 

The monthly mean streamflow of the Delaware River at Montague, N.J. during September was 2,808 cfs (observed), which was 139 percent of median. The flow at Montague, adjusted for diversions from the basin and change in storage in the major reservoirs was 2,596 cfs, or 178 percent of median (water years 1961-90).

Combined storage October 1, 2000, in Pepacton, Cannonsville, and Neversink Reservoirs was 88.0 percent of capacity above the point of maximum depletion. The combined storage of 238 billion gallons was 17 billion gallons less than that of one month ago and was 82 billion gallons more than that of one year ago. Median storage on the first day of October in 33 years of record is 177 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 September were above average in 7 of the wells. Water levels in 13 of the wells were trending downward in comparison to August levels. Water levels in 8 of the wells were above September 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 Sept. 1999

October  1999 to September  2000

 

Average

Actual

Percent of average

Excess (+) or deficit (-)

 

Amount

Cumulative

Amount

Cumulative

By month

Cumulative

By month

Cumulative

Oct.

3.40 43.24 2.72 46.70 80 108 -.68 +3.46
Nov. 3.87 39.84 2.75 43.98 71 110 -1.12 +4.14
Dec. 3.37 35.97 1.84 41.23 55 115 -153 +5.26
Jan. 3.02 32.60 3.44 39.39 114 121 +.42 +6.79
Feb. 2.64 29.58 3.26 35.95 123 122 +.62 +6.37
Mar. 3.32 26.94 4.08 32.69 123 121 +.76 +5.75
Apr. 3.76 23.62 *4.81 28.61 128 121 +1.05 +4.99
May 4.17 19.86 5.76 23.80 138 120 +1.59 +3.94
June 3.91 15.69 6.67 18.04 171 115 +2.76 +2.35
July 4.09 11.78 4.24 11.37 104 97 +.15 -.41
Aug. 3.86 7.69 3.60 7.13 93 93 -.26 -.56
Sept. 3.83 3.83 3.53 3.53 92 92 -.30 -.30

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

 

Percent of

Maximum

Median

Minimum

Monthly mean

median

September (observed 9,167  (1960) 2,016 892 (1941) 2,808 139
September (adjusted) 10,720 (1960) 1,462 324 (1964) 2,596 178
               
October (observed) 15,690 (1955) 2,326 807 (1941)    
October (adjusted) 18,570 (1955) 2,130 322 (1964)