May 2008

U.S. Water News Online

TUCSON, Ariz. -- A Green Valley company is proposing to nearly double the size of a planned pipeline to import Central Arizona Project water into the growing area, as part of an agreement to bring in CAP water for the Rosemont mine.

The proposal calls for a pipeline that would bring in more than quadruple the amount of water the original pipeline would have brought — 30,000 acre feet compared with 7,000.

That larger amount of water would eliminate or come close to eliminating the groundwater overdraft now plaguing the Green Valley area because of pumping for mines, farmers, homes and golf courses.

The newly proposed pipeline, about nine miles long, would be 36 inches in diameter compared with 20 inches in the original proposal.

But the pipeline proposal faces a big unknown making sure it stays full as population growth brings more water users into Arizona over the next 20 years. That will put more pressure on CAP's Colorado River supply, which already is over-allocated.

The Community Water Company of Green Valley hopes to get engineering and permitting work for the pipeline completed this year, start construction next year and have the pipeline on line by 2010, company president Arturo Gabaldon said.

The pipeline would allow use of CAP water instead of groundwater pumping that is lowering the water table by about 2 feet per year, according to various studies.

The CAP water would be recharged in the Green Valley area and also offset the effects of future Rosemont mine pumping.

Augusta Resource Corp. has agreed to pay the pipeline's $15 million to $18 million tab.

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