Issues: Water

An underground aquifer that sustains two Native American tribes in Arizona's arid Black Mesa region is showing signs of serious decline after three decades of pumping by the Peabody Coal Company, which drains more than a billion gallons of water from the reservoir each year to transport coal.

Approximately 40 percent of Arizona's water comes from underground sources like the one that supports the people of Black Mesa -- natural reservoirs known as aquifers that have built up stores of water over millions of years. Water that collects in the Black Mesa aquifer slowly percolates from the northwest sector of the Navajo reservation into a set of shallow, fingerlike projections near the Hopi reservation in the south, discharging after many years into a host of gentle washes and springs.

Many Hopi and Navajo rely on the aquifer for drinking and irrigation and for religious purposes -- the springs it feeds along its southern front are sacred to the Hopi people -- but the largest user by far is the Peabody Western Coal Company. Peabody mixes the water with coal to form a compound called slurry and shoots it hundreds of miles by pipeline to a power station in Nevada. Once the slurry reaches the power plant the coal is extracted and the water used to cool the plant's generators.

Since Peabody began tapping the aquifer thirty years ago, water levels in some Black Mesa wells have dropped by more than 100 feet, many springs have slackened to less than half their original volume, and washes used by local farmers appear to have declined. In addition, a government study shows that some contamination of the aquifer may be taking place, as changes in the water pressure allow contaminated water from another aquifer to leach in. Officials from the Interior Department who are monitoring the situation insist that all is well, yet their own data cannot support that conclusion. NRDC’s 2006 evaluation shows continued "material damage" in all four of the thresholds used by the government to monitor damage to the aquifer.

From the beginning, the annual withdrawal of more than a billion gallons of potable water for mining purposes caused concern. When Peabody negotiated its initial arrangement with the Hopi and Navajo in the mid-1960s, then Interior Secretary Stewart Udall included an escape clause that could be triggered if the company's pumping adversely affected the aquifer and its users. Yet despite numerous studies and now-obvious signs of negative impacts, the Department of the Interior has not exercised its contractual authority in the nearly 35 years since the original leases were signed.

The case for action is all the more compelling in light of the "trust responsibility" that the government owes the Hopi Tribe and Navajo Nation. As courts have long recognized, this responsibility obligates the federal government to protect tribal interests -- especially when the government exercises control over natural resources on tribal lands, as it does on Black Mesa. In these circumstances, its responsibility rises to the level of a fiduciary duty, similar to that which CEOs owe their shareholders or trustees their beneficiaries.

Yet Peabody's pumping continues unabated. With each passing day, another 3 million gallons (on average) are pumped from the aquifer, mixed with pulverized coal, and sent hundreds of miles away; billions more gallons will be siphoned off before operations wind down. To help solve this pressing problem NRDC recommends, in part, that Peabody permanently cease groundwater pumping in the area and that the government deny Peabody’s request for increased access to these waters. (A full list of recommendations can be found on page 16 of the updated paper.)

Based on an October 2000 report and a March 2006 issue paper, DRAWDOWN: An Update on Groundwater Mining on Black Mesa, by the Natural Resources Defense Council. See also our interview with Hopi leader Vernon Masayesva.

last revised 3.20.06