Climate variability in southeastern Pennsylvania and its impact on the Schuylkill River basin

Like most of the Mid-Atlantic region, southeastern Pennsylvania suffered through mild-to-severe drought conditions during the majority of 1999. Drought indexes finally returned to normal after a wet September that included the heavy rains from Hurricane Floyd. This paper will first examine patterns of climate variability in southeastern Pennsylvania in order to place the drought of 1999 in historical context. Preliminary work shows that precipitation data were not only low during the summer of 1999, but that the dry conditions had persisted from the previous autumn. Such variability is common in the region, though there has been a significant long-term trend toward wetter autumns. Secondly, the paper will examine the impacts of climate variability on the Schuylkill River Basin. The Schuylkill River Basin covers almost 2000 square miles of southeastern Pennsylvania before joining the Delaware River in Philadelphia. Water from the basin serves a population of over one million with more than 250 million gallons of water per day. A further 300 million gallons of water are used each day by seven thermoelectric power plants and 33 wastewater treatment facilities. Periods of low flow raise concerns about the long-term sustainability of water quantity and water quality. Flow at seven USGS hydrologic stations within the basin correlates significantly with temperature, precipitation, and the PHDI in the region, though the nature of this relationship varies seasonally. The paper concludes by tracking this relationship through time, highlighting periods of drought and reviewing the hydrologic impact.