Hydrologic Conditions Report - January 22, 1997

General

In 1996, the Delaware River Basin above Trenton received 62.04 inches of precipitation. New York City’s Delaware Basin reservoir levels currently stand at 98.3% of capacity. On January 21, net storage stood at 266.1 billion gallons (bg), which is 59.235 bg above the long-term average level, and 55.836 bg above the level of one year ago. Stream flows at Delaware River and tributary stations were well above the long-term average in December and thus far in January.

Precipitation

For the month of December, precipitation on the Delaware River Basin above Trenton averaged 8.07 inches or 4.49 inches above normal. Thus far in January, observed precipitation for the Delaware River Basin above Trenton was 1.31 inches, or 0.75 inches below normal The attached table summarizes precipitation for 1996 and thus far in 1997 for selected stations in the Delaware Basin. The attached graph shows cumulative observed versus normal inches of precipitation above Trenton since 1991. Cumulative rainfall since 1991 now stands at 8.85 inches above normal. Another attached graph displays a comparison of monthly precipitation for the years 1994 through 1996.

Stream flow

Average observed stream flow of the Delaware River at Trenton, NJ in December was 41,713 cubic feet per second (cfs) or 358 percent of the long-term average. Thus far in January, the flow at Trenton has averaged 16,545 cfs, or 159 percent of the long-term average. Monthly average observed stream flow of the Delaware River at Montague, NJ in December was 18,841 cfs or 373 percent of the long-term average. Montague's average flow during the first 20 days of January was 7,142 cfs, or 153 percent of the long-term average. Attached are graphical presentations of stream flow at Trenton and Montague for the period of January 1996 through January 20, 1997.

Storage - Lower Basin - as of January 21, 1997

Blue Marsh contains 4.763 bg usable, or 99.9% of winter-pool capacity.

Beltzville contains 13.099 bg usable, or 101.0% of capacity.

Merrill Creek contains 15.623 bg usable, or 99.6% of capacity.

Storage - New York City System

Storage in New York City Delaware Basin Reservoirs on January 21:

Pepacton 138.866 bg or 99.1% of capacity
Cannonsville 96.993 bg or 101.3% of capacity (spilling 532 cfs)
Neversink 30.241 bg or 86.5% of capacity

Total 266.100 bg or 98.3% of capacity

Long-term median storage on January 21 is 206.865 bg or 76.4 percent of capacity. Total NYC storage on January 21 was 528.181 bg usable, or 96.5 percent of capacity. Normal storage for that date is 440.192 bg usable, or 80.4 percent of capacity. Attached is a graphical presentation of New York City Delaware Basin storage from January 1996 to January 21, 1997.

Ground Water

Ground water levels in reported observation wells in the Basin remained higher than a year ago, and are above normal levels for January.

Chlorides

As of January 20, the location of the 250 ppm isochlor (the salt front) was at river mile 61, located 8 miles downstream of the Delaware Memorial Bridge and 7 miles downstream of the normal location for January at river mile 68.

R.L. Limbeck, H.P. Fielding, K.S. Heinicke--DRBC--1/21/97
Acknowledgements: NWS, USGS, NYC, Kimberly-Clark Corp.

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