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Groundwater 101: Some insight regarding a crucial resource By Emily Ellis eellis@myheraldrevie

I think this is a great article about a fundamental issue, groundwater, that Cochise County and many, many other areas in the Southwest are facing. This is being exacerbated by large industrial farms, many foreign owned, that are pumping groundwater from under land leased from the State of Arizona. Yahoo news has a good article on this and it has links to a series published by the Arizona Republic earlier this year:

Cochise County is a desert. Water is scarce, but somehow agriculture has found a way to survive, and residents have drinking water.

So where does the water come from?

The answer lies underground. Cochise County gets all its water by drilling into multiple groundwater aquifers or basins.

Beneath the sprawling desert landscapes of Cochise County, there are eight major water basins supplying water to the county’s residents. They are the Douglas basin, the Wilcox basin, the Safford basin, the Upper and Lower San Pedro basins, the San Bernadino Valley basin, the San Rafael basin and the Cienega Creek basin. Studies by the Arizona Department of Water Resources show that water levels are dropping in these basins.

According to Sharon Megdal, director of the Water Resources Research Center at the University of Arizona, one of the most important things to understand about ground water in Arizona is that it is all fossil groundwater — meaning it is stored in underground aquifers.

According to Megdal, over-pumping fossil groundwater presents two distinct problems. The first is that when the water level decreases, the storage basin can shrink through a process called compaction. This causes fissures and subsidence. It can also make recharging aquifers as a conservation tactic more difficult.

The second problem is that as the water levels decrease, water quality decreases. This causes an increased need for municipal water treatment and testing and can make water from private wells no longer safe to drink.

“Groundwater is really a very complex issue and for most of us it is out of sight, out of mind,” said Megdal.

Megdal said wherever groundwater is pumped, the biggest question is always at what rate it should be pumped at.

“When dealing with fossil groundwater, the water should be replaced at the same rate it’s being used in order to be sustainable,” she said.

But pumping at what Megdal defines as a sustainable rate is not enough to meet all the water demands in Cochise County. As a result, a decreasing water supply is a constant concern for the county. To understand these concerns, it is helpful to understand the basics of how groundwater is regulated in Arizona and Cochise County.

Water is a common resource in the United States, meaning that you can own rights to water, but water itself can never come under private ownership. Surface water sources, like the Colorado River, have specific legal doctrines to govern the allocation of water rights. Groundwater, on the other hand, is governed by the more general property law doctrines of capture and reasonable use. This leaves groundwater almost completely unregulated in comparison to surface water.

In his book “Water Follies,” Robert Glennon notes that the lack of regulation around groundwater has created a sort of tragedy of the commons in which everyone seeks to maximize their personal welfare while consequently minimizing the overall welfare of the community.

In 1980, the Arizona Legislature passed the Arizona Groundwater Management Act. This established the ADWR and created three levels of regulation for groundwater in the state.

The first level of regulation leaves groundwater still largely unregulated with only a few general statewide provisions applying. The second level is an Irrigation Non-Expansion Area. The third is an Active Management Area.

Most of the major population centers in Arizona are regulated as Active Management Areas today. However, one of the sharpest criticisms against the Arizona Groundwater Management Act has been that it leaves groundwater in rural areas almost completely unregulated.

Right now, most of Cochise County falls under the lowest level of regulation with the exception of the Irrigation Non-Expansion Area in the Douglas Basin. However, that could change in November. The creation of Active Management Areas in the Douglas and Wilcox basins is up for vote on the November ballot.


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