Water Management at Pueblo Bonito: Evidence from the National Geographic Society Trenches

Abstract

Recent archaeological investigations at Pueblo Bonito in Chaco Canyon reveal that residents constructed a large diversion channel during the eleventh century A.D. as dramatic growth resulted in the expansion of the building onto the main valley floor. Sediments in the diversion channel reflect repeated episodes of flooding, rather than slow moving water typically found in irrigation canals, and archaeobotanical data indicate deposition during late summer or early fall. Although an agricultural function is possible, the channel may have been built primarily to divert floodwaters away from Pueblo Bonito while providing a nearby water source for construction and domestic use. The diversion channel was destroyed by the entrenchment of the “Bonito paleo-channel” in the late A.D. 1000s, and then buried by a combination of cultural debris and valley flooding. Although the canyon stream system changed throughout the occupation of Pueblo Bonito, there is no evidence that the formation of a deep natural channel in the floodplain had any negative effect on the growth of the great house

Water uncertainty, ritual predictability and agricultural canals at Chaco Canyon, New Mexico

“…C04 contains evidence of canal deposits dating to the Late Basketmaker period (AD 500–750), based on an OSL age of AD 600±100 (OSM 3). The location of this canal makes the rincons the most probable source and supports Vivian’s (1972) assessment that most known stone-lined irrigation features within the canyon are associated with North Mesa rincon sources (see Wills et al 2016). Vivian (1990) documented sandstone-slab head gates and canal segments around 1km up-canyon from Op.…”

“…Sturm (2016) has found multiple overlaid field configurations in the area using ground-penetrating radar, while Wills et al . (2016) have identified a large channel that diverted floodwaters away from Pueblo Bonito, the central great house. Despite documentation of canal systems, the timing and effectiveness of these constructions for agriculture is often questioned—due in part to the lack of direct dating (e.g.…”

Evaluating the Gridded Agricultural Field Model in Chaco Canyon, New Mexico, Using Geophysical Remote Sensing

“…These geophysical analyses and results represent one aspect of a larger research program at Chaco Canyon undertaken by the University of New Mexico to investigate socioeconomic change during the Bonito Phase (Drake et al 2014; Wills and Dorshow 2012; Wills et al 2012, 2016). Much of this research has been about the interdependent roles of water and food production in the development of Chacoan society.…”

What’s new in Chaco research?

“…It is argued that sufficient food production was achieved by employing technologies, such as water-diversion features, canals, sand dune farming, ak chin fields and gridded gardens (Worman & Mattson 2010; Dorshow 2012; Wills & Dorshow 2012; Wills et al . 2014, 2016; Vivian & Watson 2015; Sturm 2016; Wills 2017). Wills (2017) suggests that the evidence for agricultural features combined with dispersed fields surrounding the canyon would have been sufficient to support the labour required for great house construction, without needing to generate large surpluses.…”