Relict canals of the Tehuacán Valley, Mexico: A Middle- to Late-Holocene dryland socio-hydrological system

Abstract

The travertine-lined irrigation canal networks of the Tehuacán Valley, Mexico allowed pre-Hispanic indigenous communities to overcome risks of crop failures in an arid setting. Segments of these systems are still in use today, therefore understanding when and how these irrigation networks functioned allows us to identify which attributes of a coupled socio-hydrological system are important for maintaining the long-term resilience of irrigation systems in drylands. This paper summarizes the results of an interdisciplinary study of this prehispanic irrigation network involving mapping, radiometric dating, and diatom analyses of materials extracted from the travertine lined canals. All of the canal networks were functioning by ca. 2000 BC, at the transition from the Late Archaic to the Formative period, which is before archeological evidence for widespread community-level aggregation. Provocatively, some canals are potentially as old as 6000–4000 BC, which would mean that hunter-gatherers initiated irrigation coevally with the introduction of semi-domesticated maize, a tropical species which would require supplemental water in this arid context. The canals both facilitated agricultural intensification and enhanced the distribution of aquatic ecosystems. The resilience of these systems to their unique spring dependent context demanded frequent maintenance and the integration of multiple canal networks to mitigate geohydrological vulnerabilities of reduced discharge. These conditions set up a long-term reciprocal dynamic between people and water in the Tehuacán Valley. The results demonstrate that rigidities inherent to tightly coupled socio-hydrological systems in dryland settings were overcome by institutional arrangements first developed by indigenous communities deep in prehistory.

Writ in water—Unwritten histories obtained from carbonate deposits in ancient water systems

“…243–250; Pons‐Branchu et al, 2018; Sbeinati et al, 2010). An alternative is 14 C dating of freshwater snails or of organic matter included in the carbonate (Blyth et al, 2017; Neely et al, 2022; Winsborough et al, 1996), using δ 13 C values to detect possible contamination with inorganic carbon. Finally, charcoal in the aqueduct inner plaster lining can be dated.…”

“…Several alternative terms have been used to describe carbonate deposits in water systems, notably travertine (e.g., Keenan‐Jones et al, 2022; Neely, 2017; Neely et al, 2022), tufa (e.g., Keenan‐Jones et al, 2008), sinter and Kalksinter (e.g., Blyth et al, 2017; Grewe, 1991; Maier, 1998; Müller, 2000; Pentecost, 2005; Schmitz, 1978; Schulz, 1986; Sürmelihindi, Passchier, Baykan, et al, 2013; Sürmelihindi, Passchier, Spötl, et al, 2013; Wilson, 2000) and carbonate concretion or incrustation (e.g., Benjelloun et al, 2019; Garczynski et al, 2005; Guendon et al, 2002). (Lime)scale is a common term for these deposits in modern pipes, heat exchangers and other machines.…”

“…This review paper focusses on carbonate deposits in Roman water systems, notably aqueducts, but conclusions drawn will equally apply to water supply systems of other cultures and ages, which we cannot all treat here. Notable examples of other ancient water systems with carbonate deposits are the Classical Greek and Hellenistic water supply systems of Greece and Turkey (Angelakis et al, 2012(Angelakis et al, , 2017Lolos, 1997;Öziş, 1994), Nabatean water systems in Jordan (Oleson, 1997(Oleson, , 2018 and pre-Columbian water channels in the Americas (Caran & Neely, 2006;Neely, 2001Neely, , 2017Neely et al, 2022;Winsborough et al, 1996).…”

Early Canal Systems in the North American Southwest

“…Of interest is when and how water-control technology developed in support of food production. Unequivocal canals date as early as 3400 BC in the Zaña Valley of north coastal Peru (Dillehay et al 2005), and intriguingly earlier 14 C dates have recently been obtained on spring-fed, travertine-lined canals in the Tehuacán Valley of southern Mexico, suggesting canal technology as early as 6000–4000 BC (Neely et al 2022); however, more work is needed to confirm these dates. Canal irrigation in the prehistoric Southwest was long believed to have been a relatively recent technology introduced by migrants from Mesoamerica around 300 BC (e.g., Haury 1976:150).…”