Hydrologic aspects of the 1998-99 drought in the Delaware River basin

Water-Resources Investigations Report 2000-4112

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A notable drought in the Delaware River Basin during late 1998 and most of 1999 had a major effect on surface and subsurface components of the hydrologic system. The drought conditions resulted from anomalous patterns in the general atmospheric circulation that diverted Gulf and subtropical Atlantic moisture away from the basin. From September 1998 to August 1999, the accumulated precipitation deficiency was greater than 12 inches in the part of the basin above Trenton, N.J. Flows in some streams, mainly in the middle and lower parts of the basin, decreased to levels near or less than those measured during the drought of the 1960's, the most severe drought of record in the basin. On several dates in August 1999, combined storage in three New York City water-supply reservoirs in the upper Delaware River Basin decreased by more than 2 billion gallons per day. The drought had a pronounced effect on ground-water levels, as the combination of below-normal recharge and elevated rates of evapotranspiration produced abnormal water-level declines and record low water levels in much of the basin. The drought was broken in mid-September 1999 when the remnants of Tropical Storm Floyd delivered drenching rains throughout the basin.

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Publication Subtype:
USGS Numbered Series
Hydrologic aspects of the 1998-99 drought in the Delaware River basin
Series title:
Water-Resources Investigations Report
Series number:
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U.S. Geological Survey
Contributing office(s):
Pennsylvania Water Science Center
v, 29 p. :ill. (some col.), maps (some col.) ;28 cm.