Archaeologists are increasingly staking a position in global change research in an effort to understand how we can best adapt to climate disruption. This includes how to meet the water needs of a growing population under a hotter climate. Because most of the world’s freshwater is used for agriculture, one avenue is to improve water efficiency in irrigation farming.
Enter Chaco Canyon. One of the debates surrounding Chaco is the area’s past agricultural productivity and how many people lived there from AD 800 to 1150. The climate is arid, and surface water is seasonal and short-lived. Add to this the fact that soils are of variable fertility, and one can sense a disconnect between impressively constructed great houses, kivas, and roads and the surrounding seemingly barren environment. Beyond asking “Why here?” is this question: How did these people feed themselves? Local food production emphasizing maize would have required some type of sophisticated water management.
As stated in the introduction, Capturing Water is the first comprehensive summary and synthesis of evidence for irrigated agriculture at Chaco, and there is perhaps no better person to accomplish this task than the late R. Gwinn Vivian. Gwinn and his father Gordon Vivian spent much of their lives documenting and interpreting water and agricultural features in the Chaco Core ( Chaco Canyon, Chacra Mesa, the lower Escavada Wash, and Lake Valley). Over several decades they documented evidence, much of it subtle, for past water control, including diversion dams, earthen canals, and stone-constructed head and field gates. More recent investigations by Samantha Fladd and other contributors to the book involved revisiting several sites documented by the Vivians, providing further evidence that the Chacoan people indeed constructed and maintained sophisticated water control systems in support of food production.
The main goals of the book are to (1) present evidence of water management strategies and infrastructure, and (2) assess agricultural potential based on environmental conditions and water infrastructure. The first two chapters provide an introduction and excellent review of some of the debates surrounding Chaco, including its population size, sociopolitical organization, and the age and complexity of its water management systems. The authors make a distinction between “water management” and “water control.” The former refers to the social mechanisms and power relationships required to collect, allocate, and use water, whereas the latter refers to the specific design and operation of facilities that collect, divert, and distribute water.
The remaining 11 chapters are organized into three parts; the first is titled “Groundwater- and Runoff-Based Farming and Other Water Use.” Several ethnographically documented farming strategies involve planting in areas where water naturally occurs seasonally. These strategies include selecting water-conserving sandy soils, ak chin floodwater irrigation, and overbank flood irrigation (floodplain farming) on large ephemeral streams. Such farming strategies leave little to no physical evidence and tend to be inferred from hydrology, soils, and ancillary features such as fieldhouses and stone field markers. The authors make a reasonable case that all these strategies were likely used to various degrees in the Chaco Core. Also discussed are the procurement of water for domestic needs and the production of mortar for architectural construction.
Part II, “Canal Irrigation Systems,” opens with a chapter reviewing evidence of precontact canal irrigation in the northern Southwest, providing context for water features in the Chaco Core. Each chapter covers a specific area: West Chaco Canyon, Central Chaco Canyon, East Chaco Canyon, and areas to the south including Kin Bineola and Kin Klizhin. These chapters detail the archaeological evidence and include recent chronometric information on the Peñasco Blanco system obtained by Vernon Scarborough and colleagues that demonstrates contemporaneity with great house construction, growth, and occupation. Most canal systems in Chaco Canyon tap into runoff from small bedrock canyons (rincons), rather than axial valley drainages. In contrast, diversion dams and canals at Kin Bineola and Kin Klizhin tap into primary drainages with large catchment areas. What we see is a diversity of water control designs tailored to each geomorphic and hydrological context.
Part III, “Water, Agriculture, and Chaco Society,” consists of two chapters. The first summarizes water control evidence and considers its implications with respect to agricultural productivity. The authors make a strong case that there was agricultural production in the Chaco Core sufficient to meet sustenance needs without the significant importation of food. The second chapter considers the sociopolitical implications of this hydraulic infrastructure, arguing that the ability to control water and produce agricultural surplus may have contributed to the development of social hierarchies through the “demonstration of power over landscape.” Additionally, the recovery of turquoise beads and selenite crystals from head-gate structures indicate ritual behavior associated with water control. As is widely recognized, canals do not necessarily lead to states or religious elites, but they do increase opportunities for social differentiation.
Capturing Water is a great reference for scholars interested in Indigenous agriculture and water management. My two small complaints are that several figures contain print too small to read without magnification (at least with my aging eyes), and the introduction would have benefited from a more polished and detailed map of the Chaco Core. Nevertheless, I believe this book is a great contribution to Southwest archaeology and provides important information regarding agricultural production at Chaco. Moreover, it succeeds in showing how landesque capital investment helped sustain Chaco’s residents for more than three centuries in a marginal agricultural environment, a lesson of modern relevance for a warming planet.
