Drought in Pennsylvania, August 1 to 31, 2002

The unseasonably warm and dry weather across Eastern Pennsylvania during the month of August intensified drought conditions. A drought emergency remained in effect for most of Eastern Pennsylvania with mandatory watering restrictions in place. Philadelphia, Montgomery and Bucks Counties were under drought warning status and asked to voluntarily conserve water. Only Carbon and Monroe Counties were in drought watch status. The Delaware River Basin Commission, which oversees water supply throughout the Delaware River Basin declared a "drought" on December 3, 2001 when the supply of water in the New York City reservoir system dropped below a designated level for early December. The commission declared a drought emergency on December 18, 2001. Both triggered additional reductions in the amount of water released from the reservoirs into the Delaware River and the amount diverted out of the Delaware River Basin to New York City and New Jersey. Diversions to New York City dropped from 800 million gallons a day to 520 million gallons a day. The emergency declaration gave the commission the power to restrict the amount of water suppliers could draw from the basin. It gave the commission the authority to take water from municipal reservoirs to maintain river levels. It could also call for water releases from federal, state and privately owned reservoirs. Water from Lake Nockamixon, the F.E. Walter Reservoir and Lake Wallenpaupack could be used to maintain river levels. Releases from the F.E. Walter Dam were reduced to one-third of normal to save water. They were last used for this purpose in the 1960s. The releases help protect the riverbank and aquatic life and also prevents salt water from flowing up the Delaware River. Salt water intrusion causes corrosion problems for industries and increases water treatment costs for municipalities that depend on the river for their water supply. Maintaining river levels are also important for groundwater reserves that are recharged by the river itself. Due to the dry August, the salt front went from mile marker 73 north to mile marker 85, eight miles farther upstream than is normal for August. The emergency declaration also gives the commission the power to request that utilities and other companies that use more than one million gallons of water a day to prepare contingency plans to use less water and submit the plans to the commission. August started extremely dry during the first three weeks. In fact Philadelphia International came within a day of tying the all-time record (25 days) for the most consecutive days without measurable precipitation during the summer. No measurable precipitation fell from July 29th through August 21st. Two significant precipitation events occurred on the 24th and 29th, but it may have come too late to help the farmers. On a county weighted average August monthly precipitation totals ranged from 1.9 inches in Carbon County to 3.4 inches in Philadelphia County. Normal monthly precipitation is around 4.2 inches. The New York City Reservoirs which feed the Delaware River decreased for 76.5 percent of capacity on August 1st to 59.7 percent of capacity on September 1st. On August 31st the salt front on the Delaware River was about eight miles farther upstream (mile marker 85) than normal. For the month streamflow on the Delaware and Lehigh Rivers was about 75 percent of normal and on the Schuylkill River was less than half of normal. Flow on smaller streams were at or near record lows. This included the Tulpehocken Creek in Berks County, Brandywine Creek in Chester County and the Chester Creek in Delaware County. August total monthly precipitation was 3.70 inches at the Reading Regional Airport, 2.68 inches at the Lehigh Valley International Airport and 2.47 inches at the Philadelphia International Airport.