UNIVERSITY PARK, Pa. -- Groundwater supplies under much of Pennsylvania that dwindled to alarmingly low levels during the drought of 1999 never fully recovered and have fallen again during this year's extremely dry weather, according to a water resources extension specialist in Penn State 's College of Agricultural Sciences.

If central Pennsylvania does not receive at least normal amounts of precipitation in late fall and winter, says Bryan Swistock, the region will face a critical situation with groundwater supplies come spring.

Fifty-five Pennsylvania counties are now under either a drought watch or drought warning issued by the Pennsylvania Department of Environmental Protection. Dry conditions are most severe in the southcentral part of the state. Long-term weather forecasts by the National Weather Service are calling for no more than normal amounts of precipitation this winter.

"But we were supposed to get normal amounts of precipitation this fall, too, and we haven't," says Swistock. "If this keeps up through late fall and winter, we will be in trouble. Public surface water supplies have mostly held up rather well so far, but there are already problems with groundwater in places. Because we can't see groundwater, the public is mostly unaware."

Effects of the drought of 1999 were felt all over the state, but it was worst in the parched east.

"In the eastern part of the state -- by any measure you care to use -- the summer drought of 1999 was as bad as they get," Swistock recalls. "But ironically, in the fall of that year, the eastern part of the state received so much rain that there were flooding problems and the groundwater recovered. Here in central Pennsylvania, however, where rains were not nearly so heavy or frequent, the groundwater never completely recharged."

The worst-case scenario, warns Swistock, would be if we had a cold, dry winter, which would freeze the ground surface and not allow any recharging of the groundwater. "If that happened," he says, "the groundwater levels would continue to decline as they have all summer and they would reach critical levels come spring."

His biggest concern over the next few months is for people who depend on wells and springs. "We are not getting the fall rains we need and the groundwater levels continue to drop," he says. "Wells are starting to go dry."

There are two windows of opportunity during the year for recharging groundwater, according to Swistock: spring and fall. The fall window is now closing. In the winter, when the ground is frozen and most precipitation falls as snow, and in the summer when trees and other plants are absorbing huge amounts of water, groundwater normally doesn't recharge.

"We have tended in the last 10 to 15 years to have short-term, extreme droughts -- we had them in '88, '91, the mid-'90s and '99," says Swistock. "That's different than in the 1930s and 1960s when we had much longer-term droughts. We had six or seven years in a row of well-below-normal rainfall then. That's a big worry, because if we ever get into a cycle like that now with our higher water consumption, we'd really be hurting."

Swistock believes development and growing population, especially in the southeastern part of Pennsylvania, are putting increased pressure on groundwater resources. "There is more competition in this state for water every day from development," he says. "We are putting more pressure on the water resources."

Groundwater mining -- taking more groundwater than the system can replenish -- is happening in places like Arizona and California, threatening long-term communities. In water-rich Pennsylvania, it is uncommon.

"But in the southeastern part of our state, groundwater mining is occurring and they have started to document continually declining groundwater levels," says Swistock. "A groundwater protection area has been established. Our groundwater supplies are not unlimited. In central Pennsylvania, we should hope for lots of snow this winter."

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EDITORS: Bryan Swistock can be contacted at 814-863-0194 or brs@psu.edu.

Contact:

Jeff Mulhollem jjm29@psu.edu 814-863-2719 814-865-1068 fax