Tucson's mayor and City Council face a decision this week with significant long-range implications to our future. Tucson has received two requests to allow connections to a pipeline it jointly owns with the Central Arizona Project south of Tucson. These connections would deliver CAP water to the upper Santa Cruz River Valley near Sahuarita and Green Valley.

One request comes from the Community Water Company (CWC) of Green Valley and Rosemont Copper. Rosemont would pay for a pipeline and in return get the exclusive use of this small water company's CAP water to recharge to partially offset the potentially unlimited groundwater pumping to use in their proposed open pit copper mine in the Santa Rita Mountains.

Another request comes from FICO, the major pecan farm south of Tucson. In 2001, FICO's farm was designated as a Groundwater Savings Facility by the state. FICO's GSF would use CAP water instead of pumping groundwater, benefiting Tucson's downstream well fields. Parties allowing their CAP water to be used on FICO's farm would receive Long-Term Storage Credits for future groundwater pumping.

Mining company Freeport-McMoRan sent a letter to the mayor and council supporting the FICO option, saying, "It is an important project for the Upper Santa Cruz region of the Tucson Aquifer Management Area."

Recently, CAP staff told city staff that both connection requests must be granted - all or nothing - though the elected CAP board has never formally acted to establish this policy. Tucson's share of this pipeline is a taxpayer-owned asset. Bureaucrats from Phoenix are telling Tucson's mayor and council what they can and can't do with our asset.

That's not how it works.

FICO can further articulate the merits of its proposal. Regardless, Tucson should unreservedly reject the Rosemont scheme because:

CWC/Rosemont's proposal doesn't address existing groundwater pumping. Rosemont would take CAP water and use it to partly replace the new groundwater pumping for its open-pit copper mine. Arizona laws allow mines to pump unlimited amounts of groundwater.

CWC/Rosemont does not yet have a recharge permit nor has it applied for one. It is currently unable to fulfill its claim that it will partly offset its groundwater pumping. More importantly, other parties will not be able use the Rosemont pipeline for recharge either.

The CWC/Rosemont proposal is premature and inconsistent with existing city of Tucson policy. The City Council has spoken against the Rosemont Mine, which is yet to be approved, with good reason. Among its many impacts to our region, the threats to our water quality and quantity are among the most devastating.

In addition to pumping a potentially unlimited amount of groundwater, the proposed mine will significantly impact the watershed by stacking mine waste up to 800 feet deep in tributaries of Cienega Creek and Davidson Canyon Creek. Both creeks are designated "Outstanding Arizona Waters" by the state and provide 20 percent of the groundwater recharge to the Tucson basin. The potential public-health impacts from mining wastes, such as arsenic getting into our water supply (investigativemedia.com), are a major concern.

Recently, Rosemont's independent auditor said there is "substantial doubt about the company's ability to continue as a going concern." Rosemont says this is normal, despite never having run a copper mine before.

Will Rosemont or a successor company have sufficient financial assurances to initiate and operate the mine, let alone post performance bonds or provide other assurances sufficient to mitigate and remediate long-term adverse impacts to the area?

In the short term, Rosemont's proposal is premature without a permit. Long term, it is bad water and environmental policy for Tucson Water ratepayers and our region.

Christina McVie is a retired registered nurse and serves as conservation chair of the Tucson Audubon Society and board chair of the Coalition for Sonoran Desert Protection. Email her at cmcvie@tucsonaudubon.org