Critics of the Big Sandy Energy Project cite their concerns about the effect of the proposed power plant on the water supply, but some of them acknowledge they lack information to prove their case.
"I have never said there is not enough water," said Gavin Fielding, a master's student and researcher at the University of Arizona in Tucson.
"I said we don't have enough information to say whether they have enough water."
Fielding, a master's candidate in the Department of Hydrology and Water Resources and a researcher at the School of Renewable and Natural Resources, has criticized a draft environmental statement overseen by a consultant for the federal Bureau of Land Management.
"My whole approach on the draft EIS was that the (information) inputs for the (groundwater computer) model were wrong," Fielding said.
"If the inputs in any computer model are wrong, the outputs have to be wrong."
The DEIS, released in June, determined that the natural gas-fired power plant would not have a major effect on the water supply because most of the water used by the power plant would come from deep wells.
Dwight Carey, an environmental consultant from Brea, Calif., who served as project manager for the draft EIS, declined to respond to Fielding's comments, adding he will respond to all comments when he releases the final EIS by late October.
"We actually prepare a final document," Carey said.
"It's a measured and tempered preparation of responses to all the comments and, if warranted, changes to the EIS."
The BLM, which has oversight over a proposed natural gas pipeline crossing its lands, commissioned the draft EIS in conjunction with the Western Area Power Administration.
WAPA oversees the electricity grid that would transmit power generated by the proposed 720-megawatt power plant.
Fielding, who is completing a study on Mohave County's water supply through a grant funded by the Arizona Department of Water Resources, questioned the assumptions in the draft EIS regarding a copper mine in Bagdad owned by Phelps Dodge.
He said the hydrologists who did the computer model assumed the open pit mine withdraws 2,000 acre-feet a year of water from the Big Sandy River aquifer.
"My own research shows it is more likely to be around 8,000 acre-feet per year," Fielding said.
The power plant, proposed by Big Sandy Caithness LLC of New York City, is expected to use 2,400 to 2,500 gallons of water per minute, according to county planning and zoning department staff.
Fielding said he is trying to get figures from the mine.
Bruce Richardson, a spokesman for Phelps Dodge in Phoenix, declined to release information to the Miner on how much water the open pit mine uses, but indicated that the Big Sandy aquifer accounts for no more than half of the water.
Wells near the mine account for the remainder of the water.
"Water is a very sensitive issue," Richardson said.
"We are involved in water issues around the state concerning water rights.
It's sensitive and in many cases it's a competitive issue.
Water has value.
It's just not something that we freely talk about."
Fielding said the computer model relied on water levels in the Big Sandy valley between 1959 and 1971, figures that he considers outdated because the copper mine did not start pumping water until the late 1970s.
He said wells drilled as part of the hydrology study are very "site specific" and will not indicate what water levels are a half-mile or more away because of different rock formations.
Jack Ehrhardt of Citizens for Future Generations has opposed the Big Sandy project for some time, and was scheduled to attend a meeting of the Arizona Power Plant and Transmission Line Siting Committee Wednesday in Phoenix.
The 11-member panel is considering whether to issue a certificate of environmental compatibility, which would enable Caithness to build the plant.
Ehrhardt said Fielding's presentations on the power plant to the Northwest Arizona Watershed Council reinforced his opposition, adding he lacks independent data to dispute the findings of the draft EIS.
"The original opposition is you don't go in and jeopardize a natural, free-flowing river and habitat," he said.