On March 20, 2003, Governor Janet Napolitano issued Executive Order 2003-12 creating a Drought Task Force to identify and plan responses to potential problems resulting from the current drought. Among the issues being evaluated are: potentially low supplies of potable water for water providers, drought-related water level declines that can cause a loss of supply for individual domestic wells, insufficient water supply for crops and livestock, and impacts to wildlife and wildlife habitat due to reduced availability of water.

All of these issues are of interest to the residents of the Globe-Miami area, including the Pinal Creek Group, as we work to manage our water resources wisely.

The Drought

Another factor contributing to the increased density of native plant species is a livestock management plan that controls grazing in several pastures along perennial Pinal Creek. The construction of fences has made it possible for riparian habitats to recover while still providing enough pasture to meet landowners’ grazing needs. Fenced areas are either closed entirely to grazing or are closed to grazing each year from April through October. In certain areas winter grazing may be allowed. As a result, willows and cottonwoods are becoming well established along several portions of perennial Pinal Creek, with both species exhibiting significant increases in the five years since the riparian management program was implemented.

Drought is a sustained, natural reduction in precipitation that negatively affects the environment and human activities. Short-term droughts are limited to periods of several months and, while inconvenient, they are transient. Long-term droughts, on the other hand, can last for years and may significantly affect the availability of both surface and subsurface water supplies.

Arizona has been subject to several major statewide droughts occurring from the late 1890s through the early 1900s, the late 1940s through the mid-1960s, and the current cycle that began in the late 1990s. Droughts such as these result from below-normal rainfall and snowfall, and consequently, less runoff to surface water streams and less recharge to groundwater aquifers. The effect of these droughts on surface water in Arizona is illustrated by the change in annual average streamflow of the Salt River, as shown by Figure 1.

When drought occurs, water levels in groundwater aquifers can drop significantly. The graph in Figure 2 illustrates the water level in the Gila Conglomerate near Wheatfields. The increase in water levels during the rainy period of the early 1990s is clearly shown, as is the continued decline of low water levels through the current drought period. It could take several years to replenish the groundwater supply depending on the rates at which water is depleted from and recharged to the aquifer.

During a sustained drought, a substantial drop in groundwater levels due to reduced aquifer recharge can place small capacity domestic wells at risk of lowered production or going dry. During times of lower than normal water levels, overlapping pressure from other, nearby pumping wells can cause further water level decline. Where water supplies are dependent on groundwater pumping, water conservation and good well maintenance practices are essential to minimize the effects of drought.