“A Never-Ending Source of Water”: Agriculture, Society, and Aquifer Depletion on the Coast of Hermosillo, Sonora

Introduction

This article analyzes the evolution of irrigation and water use in the region of the Hermosillo Coast, in the Mexican state of Sonora. Over the last 60 years water use in this region has supported an agricultural development model the principal characteristic of which has been inequality: in the access to that resource; in the distribution of economic benefits; and in the distribution of social and environmental costs. Repeated legal and political efforts to limit subsoil water extraction have failed for the most part, and the depletion of the aquifer has led to saltwater intrusion from the Gulf of California, soaring energy costs for deep wells, and immanent water shortages.

The history of the Hermosillo Coast region shows that this kind of development is unsustainable over the long term because it favors narrowly conceived economic objectives at the expense of social and environmental objectives. It has, moreover, favored a small group of people. In physical, environmental terms the development model has, from its inception, depended on the extraction of subsoil water far beyond the ability of natural recharge to replenish the source, thus threatening the future existence of agriculture and urban centers in the region. In economic terms, the unsustainability of the development model can be seen in subsidies to electricity, water, and crop prices that have promoted the wasteful use of aquifer water. In social terms, aquifer-fed agricultural development in this region has proven unsustainable because it has produced the intrusion of seawater into the aquifer in the coastal zone inhabited by small-scale farmers known as colonos. While efforts to relocate the colonos did not succeed, this in turn meant that these small producers continued to farm with substandard water, negatively affecting their businesses and accelerating the process of land and water concentration in the hands of a few wealthy families. By the late 1990s, 70 percent of the small colono producers who had settled during the golden age of agriculture in the 1940s had been forced to sell or rent their lands. The state has played a crucial role in securing the interests of regional elites and transferring the costs of this development model to other social groups as well as the environment. Examples of this include the relocation of wells, subsidies, and “special water concessions” that are given to certain producers to take advantage of market conjunctures. Because of its role in the development model, the state is unable to carry out its own declared intentions of regulating and reducing water extraction.

Geography and Early History

The deep-well irrigation district of the Hermosillo Coast is located on the central coastal plain of the state of Sonora. It forms part of the large geographic region known as the Pacific Coastal Plain, which is sandwiched between the Sierra Madre Occidental mountain chain on the east and the Gulf of California to the west. In general it is a flat area that slowly descends from the city of Hermosillo, at 200 meters above sea level, to Kino Bay (Bahía Kino), about 100 kilometers away. The soils are made up of alluvial sands and silts deposited by watercourses over thousands and millions of years. This soil composition together with the topography favored the filtration of surface water and the formation of rich aquifers. The climate is very dry and hot during the summer with occasional rains, and the temperature can fall to freezing in the winter.

The zone is considered semiarid because it receives only between 75 and 200 millimeters of rainfall annually. These scarce rains are also erratic, and can fall in late winter as well as in mid-summer, a pattern typical of the border region. The summer rains result from tropical weather systems and are usually intense and localized downpours that create great torrents in the watercourses of the region. The winter rains are those that sweep down from the northern Pacific, and are usually lighter and longer lasting. Due to intense heat and dryness in the region, annually three times more water evaporates than falls...