Nearly 2 million acres of natural splendor straddling Virginia and West Virginia make up the George Washington National Forest. (Jared Soares/For The Washington Post)

George Washington National Forest is more than just one of the largest expanses of pristine land in the East. It’s the leafy cradle of the Shenandoah, James and Potomac rivers, a source of drinking water for millions of people in greater Washington.

The forest — nearly 2 million acres of natural splendor straddling Virginia and West Virginia — might also hold another treasure: natural gas trapped under a deep layer of rock called the Marcellus Shale.

By the end of the month, the U.S. Forest Service is expected to decide whether to ban or allow the controversial method of drilling called hydraulic fracturing under the forest’s new, 15-year management plan. The decision will settle a raging dispute between conservationists and the oil and gas industry.

The oil and gas industry argues that it would be unfair for the government to “slam the door” on hydraulic fracturing in the forest for such a long period of time, and points out that natural gas is a cleaner fuel than coal. Conservationists say the drilling method, also referred to as fracking, could contaminate water at its source. The process involves drilling a deep vertical well, then bending it horizontally so millions of gallons of water and toxic chemicals can be blasted into the earth to fracture shale and release gas.

The Forest Service proposed banning the practice two years ago, a move criticized by Gov. Robert F. McDonnell (R) as overreach. But the proposed ban is backed by two agencies that provide drinking water to 4.5 million customers from the Potomac: the Army Corps of Engineers — which operates the Washington Aqueduct, from which the District, Arlington County and Falls Church withdraw water — and the Fairfax County Water Authority.

Jobeh Moore, 7, lays on his back while cooling off in Passage Creek within the George Washington National Forest outside of Front Royal, Va. July 17, 2012. (Matt McClain/The Washington Post)

Thomas P. Jacobus, the aqueduct’s general manager, called the forest streams and rivers “a key resource,” and said in a letter to the Forest Service that anything that undermines agreements made by states to preserve the water quality of the Potomac “would be unwelcome. Safe water supply is essential to life.”

Assessing the stakes

One hundred species of fish and mussels live in the shallow waters of the Cowpasture and Jackson rivers, which gurgle in the forest along the Appalachian spine. There are also 70 types of amphibians and reptiles, 180 species of birds and 60 species of mammals. The list of all the trees, plants, fishing areas, hiking trails and campsites could fill a book.

The forest streams and rivers, called headwaters, form in the region’s highest elevations and flow down. They are the origin of the Potomac’s drinking water and provide the water that created the James and Shenandoah rivers.

The officer in charge of drafting the final management plan said he understands the stakes of allowing drilling with chemicals in one of the most pristine forests on the East Coast.

“If you had a pollutant anywhere in the watershed, it would be a concern,” said Ken Landgraf, planning staff officer for George Washington National Forest. “But in the headwaters, everyone would have to deal with that. Everybody’s going to see that further downstream in the watershed.”

Another concern is that, wastewater bubbles back to the surface during the process and must be stored in sealed containers that have been known to leak. Moreover, dozens of heavy trucks carry the mixture of water and chemicals to and from the drilling sites, sometimes spilling it.

More than 500 million cubic feet of gas is entombed in Marcellus Shale, which runs 95,000 square miles between Virginia and Ohio. Fracking wells in Pennsylvania, West Virginia and Ohio have generated significant profits, as well as major concerns over safety.

The government has allowed oil and gas drilling on other public lands, mostly in the West, where it owns large tracts of wilderness. Production from about 92,000 oil and gas wells on public lands makes up about 13 percent of the nation’s natural-gas production and 5 percent of its oil production, according to the Interior Department.

The Bureau of Land Management administers about 700 million acres of land holding mineral resources, and Chesapeake Energy and other natural gas explorers are pressing officials for wider access to them.

Landgraf said his team has pored over studies in New York, where hydraulic fracturing operations were numerous before a 2008 moratorium put them on hold. In addition, they have relied on records of safety incidents in Pennsylvania and West Virginia, along with BLM and U.S. Geological Survey records on fracking, to make their determination.

Under the current management plan, initiated in 1993 and originally set to expire in 2008, limited drilling was allowed. But, even though 12,000 acres are under lease by oil companies, the drilling never happened, in part because getting a permit was difficult. Companies first were required to In get permission from the BLM to lease land where they might drill, Landgraf said. Then, to actually drill, companies were required to pay for an environmental-impact study, which could easily be denied.

Fracking’s past and future

Shale gas is “a potential domestic resource that at some point in time can be safely extracted,” said Mike Ward, executive director of the Virginia Petroleum Council, a nonprofit group that advocates for the oil industry.

“We want flexibility to operate if improvements in the technology allow it,” Ward said. “The Forest Service has been flexible about this for so many years. They don’t have to issue any leases. To put a moratorium upfront slams the door without any further consideration.”

In nearby Jefferson National Forest, “we’ve had traditional gas-drilling operations for years, never a problem,” Landgraf said, referring to vertical wells. But horizontal drilling, with its chemicals, wastewater pools and truck hauling, is another story.

For decades, few people seemed to care about drilling in the forest, Landgraf said. But two years ago, several oil companies descended on Rockingham County just outside the forest and leased land, with an intent to drill.

County commissioners blocked their efforts because of concerns about how the companies would store wastewater and how much they were prepared to pay in the event of chemical contamination.

The commissioners refused to approve a land-use permit for the operations, effectively killing the plans. That fight played out just as forest officials were finishing the first draft of the management plan. Conservationists, water authorities and sports fishermen rallied against fracking in the forest.

“The waters need to be quite clean for trout to survive,” said Thomas Benzing, vice president of conservation for Trout Unlimited in Virginia and a James Madison University science and technology professor. Some wastewater could be toxic to trout, Benzing said, though he could not cite any incidents in which fracking killed trout.

“Why would the Forest Service gamble with the drinking water of more than 4 million people?” asked Dusty Horwitt, a senior analyst for Earthworks, a nonprofit environmental group. “Why allow an industrial drilling process in our watershed that involves thousands of truck trips, millions of gallons of toxic fracking fluid and millions of gallons of potentially radioactive wastewater?”

Water contaminated in the forest could easily wind up in the Chesapeake Bay, said Mark Bennett, director of the USGS water science center for Virginia and West Virginia.

“Because that’s where it’s headed.”