Scientist warns of adverse effects of excess CBM water - prediction based on 'modeling'

By CLAIR JOHNSON
Of The Billings Gazette Staff

10/30/03

Gore's projections are based on computer models of river systems in Montana and Wyoming...

Increased river flows from carrying coalbed methane discharge water could eliminate up to 30 aquatic species within 20 years, according to study of Montana and Wyoming rivers by a water resources expert.

James Gore, an environmental science professor at Columbus State University in Georgia, also found that the long-term threat of increased flows would affect up to 80 percent of the fish and other organisms that use shallow water habitats for feeding and cover.

Gore, who serves on a U.N. scientific advisory panel on water resources, will present his research during a session on coalbed methane at the 10th International Petroleum Environmental Conference Nov. 11-14 in Houston.

While drilling for coalbed methane, a form of natural gas found in coal seams, has attracted a lot of interest, industry leaders want to know the environmental price to be paid, Gore said.

Gore is well acquainted with Montana and Wyoming river systems, having conducted studies in the Powder River Basin as a University of Montana graduate student and doctoral candidate in the 1970s.

Tom Richmond, administrator of the Montana Board of Oil and Gas Conservation, also is scheduled to give a presentation at the conference on designing a regulatory program for coalbed methane in Montana.

Abstracts of Gore's study and Richmond's paper are available on the conference Web site at ipec.utulsa.edu.

Drilling for coalbed methane requires discharging large volumes of ground water, which holds the gas in coal seams through pressure. The ground water is often salty, which can damage plants and soils. The main methods for disposing of coalbed methane water are dumping it in rivers and streams and storing it in reservoirs or ponds.

Gore's projections are based on computer models of river systems in Montana and Wyoming where an increasing number of coalbed methane wells each discharge as much as 17,000 gallons of salt water daily. About 60 to 80 percent of the discharged water finds it way back in to nearby rivers and streams, he said.

The resulting periodic overflow is affecting species such as the endangered Western silvery minnow, which is found in the Powder and Belle Fourche rivers in Wyoming, he said.

Gore and other scientists have raised concerns about how coalbed methane development could affect water systems, including groundwater aquifers and rivers and streams. Other concerns involve the potential long-term consequences of aquifer depletion, soil degradation and land erosion.

Gore's study looks at the elimination of river habitat caused by overflows of coalbed methane water. The increased volumes of water disrupt shallow water habitats that are vital to the river's food chain, such as snails, shrimp, worms and insect larvae and ultimately the newborn fish that feed on those organisms, he said.

"Based on the increase in flow volume alone, we're looking at the elimination of 20 to 30 species over the course of 20 years where the process is applied," he said.

People immediately think of fish, Gore said, but there are as many as 50 to 60 species of invertebrates in the water.

Gore's analysis looked at water quantity and assumed the quality was "perfect." If the salinity of coalbed methane water is considered, "you accelerate the loss of species further," he said.

The problem comes when water levels increase to constantly higher flows and alter the habitat over the long term.

If organisms are forced to live outside their range, they can get "blown out of the system," Gore said. For example, faster water can damage an organism's filtering nets that strain food particles from the water and thereby cause the organism to starve.

Gore said the potential consequences of increased flows range from harming recreational fishing to the continued deterioration of the ecological integrity of the planet.

"The question industry and government officials have to consider is: Is this degree of ecological destabilization a worthwhile trade-off?" he said.