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.

STREAMFLOW, IN CFS DELAWARE RIVER AT MONTAGUE, N.J.
Month	1940-98				1999	Percent of
Month	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)