"Sometimes a creek will be almost dry with a few pools. Then it will rain, and there will be a big blowout," Davis said, describing the flooded creeks she saw last summer. Davis is a Montana State University graduate student who spent May through August collecting information to see how coal bed methane development affects fish.
Davis and technician Ryan White sampled about 6,500 fish in 19 tributaries of the Tongue River, Powder River and Little Powder River last summer. Davis plans to return this summer, possibly with two technicians, to the 54 sites she sampled in 2005 and 15 new sites on six more tributaries. All the streams are on private land.
"The Powder River Basin in Wyoming and Montana is currently undergoing one of the world's largest coalbed natural gas developments with about 12,000 wells in place in 2003, 14,200 in 2005 and up to 70,000 projected over the next 20 to 30 years," Davis wrote in a project summary. "Because coalbed natural gas development involves production and disposal of large quantities of coalbed ground water that differs from surface waters, potential exists for substantial effects on aquatic ecosystems."
High concentrations of dissolved solids, including sodium and bicarbonate ions, are typically found in water associated with coalbed methane, Davis said. Little is known about their effect on fish in the Powder River Basin, however.
She is taking four approaches to find out, Davis said. One compares fish in streams that have coalbed methane development and streams that do not. The second compares fish at various points in a stream. Some of the points are above and some are below the development. The third compares fish before and after development started. The fourth compares fish today with fish surveyed in the mid-1990s. Today's fish would have been exposed to coalbed methane development, and the earlier fish wouldn't have been.
Her results won't be ready until the spring of 2007, but she can say that fish are abundant in the Powder River Basin, Davis said. She also found some normal, healthy fish swimming in water that was completely associated with coal bed methane exploration.
"There's some speculation that when you take all this water out of the ground, it might cause some springs to dry up," Davis said. "Or when you hold water in ponds, it might seep into the streams."
Bob Bramblett, an MSU researcher who started sampling Montana's prairie streams in 1999, said he has documented 49 fish species in the small streams of Eastern Montana. Sampling a portion of them in her study, Davis said the fish she found ranged from one-inch minnows to 20-inch channel catfish.
"It's the first time a lot of these creeks have been sampled," Davis said. "Because the fish were not game species, they weren't considered important for management."
Bramblett said the Wyoming streams Davis surveyed are in the same type of environment as the streams he sampled in Montana. Both are semi-arid, prairie areas.
"A lot of these small streams we sampled are intermittent, which means they don't flow year-round," he added. "Most of them do tend to maintain some pools that are permanent. Those are places where fish can survive."
Davis said the main goal of her study is to provide objective, scientifically sound information to agencies, industry and tribal leaders who make decisions about the land and water in Montana and Wyoming.
Bramblett and Alexander Zale, both with the Montana Cooperative Fishery Research Unit based at MSU, are Davis' advisors. Davis' study is funded by the Bureau of Land Management, the Montana Water Center and the U.S. Department of Energy.
Evelyn Boswell, (404) 994-5135 or firstname.lastname@example.org