Jan 16, 2015 3 min read

Natural gas drilling companies use millions of gallons of water to hydraulically fracture a well, and state waterways are being tapped to meet the industry’s demand for fresh water.

In Pennsylvania, oil and gas companies must follow a water management plan approved by the state Department of Environmental Protection, which determines how much water they can remove at any given time.

Dan Counahan, environmental group manager for the DEP, explained the company must first conduct preliminary and hydrological studies on a waterway to determine the stream flow and any impacts from the water withdrawals. From there, companies propose a daily amount and maximum rate to withdraw water at a particular site.

The DEP then reviews the tests and plugs the data into a computer system, which determines if the site already has a pass-by restriction, meaning the withdrawal limit already was reached at that location.

The amount companies can withdraw is based on a Q7-10 formula, which is the “actual or estimated lowest seven-consecutive-day average flow that occurs once in 10 years for a stream with unregulated flow, or the estimated minimum flow for a stream with regulated flow,” according to Pennsylvania Code. Companies can withdraw 10 percent of that average flow before reaching a pass-by restriction.

“Any (company) that is in pass-by needs to check the flow rates before they begin withdrawals, and every authorization, whether or not it has a pass-by associated with it in their plan, needs to be checked when it gets relatively low,” Counahan said. “All operators have to cease withdrawals when it reaches that Q7-10 level.”

In instances where one waterway is being tapped in various locations, like Ten Mile Creek, the DEP looks at the cumulative assessment of the waterway to see if a pass-by restriction is warranted. In some cases, the DEP puts conditions in the operator’s water management plan to restrict water withdrawals to one site at a time within a 24-hour period.

Counahan said all water-management plans adhere to the state Fish and Boat Commission’s standards, and the larger waterways generally are not impacted by water withdrawals.

“We’re very fortunate to have these three large rivers here with an excess of water, where a million gallons a day isn’t going to have even a measurable effect on the water levels,” he said.

The DEP periodically conducts inspections at water withdrawal sites, but Counahan said it’s difficult because about seven times out of 10, inspectors go out to a site only to realize it is not active.

Many companies also utilize water recycling practices, which reduce the need to remove water from rivers and streams.