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CASPER - Some areas of the Powder River Basin have experienced significant groundwater drawdown - as much as 625 feet between 1993 and 2006 in some areas, according to a new report.

But what the report is missing is analysis to determine whether the impact is in line with federal modeling conducted in 2002.

However, some say the raw data reveals obvious impacts to groundwater supplies.

The Powder River Basin Resource Council issued a statement Tuesday suggesting that the monitoring data proves the actual groundwater drawdown - largely from the development of coalbed methane gas - far exceeds predictions made by federal officials in 2002.

"Many of these aquifers in the arid West take 10,000 years to recharge to the levels they had before (coalbed methane) depletion, according to some hydrologists," PRBRC chairman Bob LeResche said.

About 600 million barrels of water are pumped from coal aquifers in the Powder River Basin each year in the production of coalbed methane gas, according to the state. Some of the water is used in irrigation and to water livestock, but a majority of the water - which belongs to the state - is not put to a specific beneficial use.

The groundwater monitoring report by the Wyoming State Geological Survey and Wyoming Bureau of Land Management is a compilation of data collected from 1993 to 2006. BLM officials warned that the report is an "open file report," meaning actual analysis of the data is not completed.

Initial modeling of groundwater drawdown was conducted in 2002 based on an estimated 39,367 new wells between 2002 and 2011. Based on that scenario, the report would indicate that the actual drawdown is less than was predicted.

But the industry isn't on course to hit the 39,367 wells scenario by 2011. As of September 2008, a total of 29,719 coalbed methane gas wells had been drilled in the Powder River Basin, and that includes thousands of wells drilled before 2002. Drilling has slowed to a halt in 2009.

The industry has harvested less than 12 percent of the estimated coalbed methane resource in the basin.

Federal officials say because the actual level of development has been less than predicted, the original model must be recalibrated to understand the actual impact on groundwater resources.

"We agree that this is not the final report and there's a lot more analysis that needs to be done," said Kathy Brus, supervisory natural resource specialist in the BLM Buffalo field office.

A large amount of baseline data is missing as well, because in many cases coalbed methane wells began pumping water before monitoring could begin.

Brus said monitoring and analysis will continue, in addition to an effort attempting to estimate baseline groundwater levels. She said the report was made available because many stakeholders are interested in the information. While it took three years to compile 13 years of groundwater data, the hope is to issue more frequent reports in the future.

Much of the data was compiled by Keith E. Clarey of the Wyoming Water Development Commission. Clarey said some areas where coalbed methane gas activity has concluded have actually experienced significant recharge.

He said the monitoring data also indicates there is a correlation between water drawdowns in coal seams and water drawdowns in the overlying Wasatch standstone - but with wide variation. In fact, water levels have risen in some areas of the Wasatch.

"It's a very complex issue," Clarey said.

Under Wyoming's current legal view, the "beneficial use" of some 44.1 billion barrels of water residing in coal aquifers in the state is the actual production of the methane gas that also resides in the coal. Methane is held in the coal under water pressure, so by pumping water out the pressure is relieved, releasing the gas.

LeResche said the impact on groundwater resources is huge, particularly for numerous landowners who have lost domestic, livestock and artesian, or free-flowing, wells in the basin. In fact, many properties that experienced such problems have been bought out by coalbed methane developers.

He noted that Interior Secretary Ken Salazar has acknowledged water issues will dominate his department for years to come.

"The BLM, which falls within the Interior, must not only acknowledge that (coalbed methane) development is rapidly depleting water supplies that Westerners depend on, but also must do something to stop the loss," LeResche said.

Campbell County rancher Eric Barlow said residents across the state should be concerned, because the groundwater is a resource that belongs to all Wyomingites.

"At same time we are gaining mineral revenues we are losing a water resource," Barlow said. "This is an exceptionally water-resource-intensive industry."

Contact Dustin Bleizeffer at 307-577-6069 or dustin.bleizeffer@trib.com.

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