Three million gallons of water a day sounds like an enormous amount to take from the Susquehanna River — or any natural waterway.

But the Susquehanna withdrawals planned by Aqua America and Penn Virginia Resource Partners are only a fraction of water removed from all Pennsylvania water sources.

Officials of the Susquehanna River Basin Commission did not respond to requests for comment  on its approval of the withdrawals, but the agency’s March 15 meeting minutes show staff determined “no adverse impacts are anticipated by the operation of this project.”

More than 560 million gallons daily were taken from the Susquehanna in 2010 for various uses, including public water supplies, power generation, and recreation, according to the commission’s latest State of the Susquehanna report.

Statewide, about 10 billion gallons are being withdrawn each day for all uses, said David Yoxtheimer, who works for the Penn State Marcellus Center for Outreach and Research.

Natural gas companies withdrew an average of 10 million gallons per day from the Susquehanna Basin last year, and the industry took another 5 million gallons of water per day from other water sources in Pennsylvania, Yoxtheimer said.

“It is a pretty small volume comparatively,” Yoxtheimer said, adding that withdrawals are scrutinized to “ensure no measurable impacts.”

Michel Boufadel, a hydrologist and environmental engineering professor at the New Jersey Institute of Technology, said he agrees the commissions for the Susquehanna and Delaware rivers carefully monitor withdrawals to ensure streams are not depleted, but he thinks the agencies overlook vital aspects of the waterways.

“The missing link is the role of environmental flow,” said Boufadel.

Environmental flow refers to the quality of water flow that keeps the ecosystem thriving, he said. Boufadel is not aware of any studies that assess the ecological impacts of withdrawals.

“Environmental flow can fall naturally, but now it is happening because of human intervention,” Boufadel said. “I’m not saying there is a negative effect, but it is something we don’t know.”

There are about 5,800 Marcellus gas wells in the state, Yoxtheimer said.

As of March, the Susquehanna River Basin Commission reported it had approved water extractions totaling about 91 million gallons daily from 173 river locations for natural gas well development at nearly 2,000 drilling sites.

An explanation of the withdrawals by the commission cautions that the maximum amount allowed is misleading because it is “highly unlikely” peak withdrawals will occur at all locations.

The commission also imposes protective conditions, including mandated reporting and levels at which withdrawals must stop to avoid drought conditions.

The Susquehanna Basin has experienced droughts eight times since 1990, according to a 2010 commission report. Water withdrawals can also affect wetlands, fish migration, recreation and other water users, the report said.

Reach Halle Stockton at 412-315-0263 or at

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Halle is executive director, editor-in-chief of PublicSource. She has served as editor-in-chief since May 2022 after seven years as managing editor during which PublicSource won two consecutive international...