In 1968, a 54,000 acre coal mine commenced operations on Black Mesa, Arizona, an arid and semi-arid region inhabited by the Hopi Tribe and Dine Nation. The coal mine fuels the power plant that generates electricity for the Central Arizona Project, which pumps renewable Colorado River water to Phoenix and Tucson. Water for mine-operations is pumped from a non-renewable groundwater aquifer upon which the Hopi and Dine depend. After forty years of development, conflict characterizes industrial groundwater exploitation on Black Mesa; there continues to be little understanding of the relationship between industrial withdrawals and its impacts upon hydrological and social-ecological systems of the region.Large-scale natural resource development is predicated upon deterministic studies required to disclose all potentially adverse impacts. This study performs a postaudit of groundwater model predictions used to determine the significance of these impacts. It demonstrates that drawdown caused by the mine was underestimated; drawdown caused by communities was overestimated; the models failed to capture the linear relationship between water level decline and spring discharge; and water levels predicted to recover by 2007 continue to decline in 2010.The Regulatory Authority developed four criteria for determining if damage to the aquifer had occurred in response to mining; over time, two damage thresholds were crossed and two had never been evaluated. A new model was implemented for regulatory purposes; simulations showed that a distant spring 60 miles from the mine is unaffected by the mine's withdrawals. The postaudit demonstrates how declining discharge from this spring has a strong relationship with industrial withdrawals (r = -0.84; R2 = 0.71; p < 0.0001); local pumping and precipitation have no statistically significant relationship with discharge from this spring.In 2008, the Regulatory Authority revised the four threshold criteria; all negative trends were removed from regulatory purview (including spring discharge) and remaining criteria assumed insurmountable damage thresholds; their condition will be determined by model simulations rather than actual observations.The Black Mesa case study reinforces the argument that the legislatively required process for predetermining environmental impacts is an elaborate ritual in which a manifestly political decision is disguised as unbiased scientific fact.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/196061 |
| Date | January 2010 |
| Creators | Higgins, Daniel Brott |
| Contributors | Hutchinson, Charles F., Hutchinson, Charles F., Orr, Barron J., Marsh, Stuart E. |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | text, Electronic Dissertation |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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