skip to main content

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

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.

more » « less
Author(s) / Creator(s):
 ;  ;  
Publisher / Repository:
SAGE Publications
Date Published:
Journal Name:
The Holocene
Page Range / eLocation ID:
p. 1422-1436
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    Built infrastructure for water and energy supply, transportation, and other such services underpins human well‐being and socioeconomic development. A fundamental understanding of how infrastructure design and user strategies interact can guide important design decisions as well as policy formulation for ensuring long‐term infrastructure viability in conjunction with improved individual user benefits. In this work, an agent based model (ABM) is developed to study this issue for the specific case of irrigation canals. Cooperatively maintained irrigation canals serve essential roles in sustaining agriculture‐based economies in many regions. Canal system design can strongly affect benefits derived by distributed users, regional agricultural output, and the long‐term viability of the shared infrastructure itself. Here, an ABM is used to investigate how an option to use an independent water source interacts with canal design to affect canal maintenance cooperation and farmer income. The independent water source is stylized as a well that provides access to groundwater and represents astrategically robustdesign option; a design option that reduces the implementer's utility vulnerability to unfavorable actions by other actors. Research in other systems has demonstrated that strategically robust designs can improve both implementer utility and the probability of collaboration. The results of this research, in contrast, demonstrate that the option of individual resource access, the strategically robust design option, as represented by a well, reduces cooperative maintenance in most cases. However, wells also improve farmer income, especially for downstream farmers that are most affected by water theft.

    more » « less
  2. Abstract

    Tropical floodplains secure the protein supply of millions of people, but only sound management can ensure the long‐term continuity of such ecosystem services. Overfishing is a widespread threat to multitrophic systems, but how it affects ecosystem functioning is poorly understood, particularly in tropical freshwater food webs. Models based on temperate lakes frequently assume that primary producers are mostly bottom‐up controlled by nutrient and light limitations, with negligible effects of top‐down forces. Yet this assumption remains untested in complex tropical freshwater systems experiencing marked spatiotemporal variation.

    We use consolidated community‐based fisheries management practices and spatial zoning to test the relative importance of bottom‐up versus top‐down drivers of phytoplankton biomass, controlling for the influence of local to landscape heterogeneity. Our study focuses on 58 large Amazonian floodplain lakes under different management regimes that resulted in a gradient of apex‐predator abundance. These lakes, distributed along ~600 km of a major tributary of the Amazon River, varied widely in size, structure, landscape context, and hydrological seasonality.

    Using generalised linear models, we show that community‐based fisheries management, which controls the density of apex predators, is the strongest predictor of phytoplankton biomass during the dry season, when lakes become discrete landscape units. Water transparency also emerges as an important bottom‐up factor, but phosphorus, nitrogen and several lake and landscape metrics had minor or no effects on phytoplankton biomass. During the wet‐season food pulse, when lakes become connected to adjacent water bodies and homogenise the landscape, only lake depth explained phytoplankton biomass.

    Synthesis and applications. Tropical freshwaters fisheries typically assume that fish biomass is controlled by bottom‐up mechanisms, so that overexploitation of large predators would not affect overall ecosystem productivity. Our results, however, show that top‐down forces are important drivers of primary productivity in tropical lakes, above and beyond the effects of bottom‐up factors. This helps us to understand the enormous success of community‐based ‘fishing agreements’ in the Amazon. Multiple stakeholders should embrace socio‐ecological management practices that shape both bottom‐up and top‐down forces to ensure biodiversity protection, sustainable fisheries yields and food security for local communities and regional economies.

    more » « less
  3. Nicewonger, Todd E. ; McNair, Lisa D. ; Fritz, Stacey (Ed.) At the start of the pandemic, the editors of this annotated bibliography initiated a remote (i.e., largely virtual) ethnographic research project that investigated how COVID-19 was impacting off-site modular construction practices in Alaska Native communities. Many of these communities are located off the road system and thus face not only dramatically higher costs but multiple logistical challenges in securing licensed tradesmen and construction crews and in shipping building supplies and equipment to their communities. These barriers, as well as the region’s long winters and short building seasons, complicate the construction of homes and related infrastructure projects. Historically, these communities have also grappled with inadequate housing, including severe overcrowding and poor-quality building stock that is rarely designed for northern Alaska’s climate (Marino 2015). Moreover, state and federal bureaucracies and their associated funding opportunities often further complicate home building by failing to accommodate the digital divide in rural Alaska and the cultural values and practices of Native communities.[1] It is not surprising, then, that as we were conducting fieldwork for this project, we began hearing stories about these issues and about how the restrictions caused by the pandemic were further exacerbating them. Amidst these stories, we learned about how modular home construction was being imagined as a possible means for addressing both the complications caused by the pandemic and the need for housing in the region (McKinstry 2021). As a result, we began to investigate how modular construction practices were figuring into emergent responses to housing needs in Alaska communities. We soon realized that we needed to broaden our focus to capture a variety of prefabricated building methods that are often colloquially or idiomatically referred to as “modular.” This included a range of prefabricated building systems (e.g., manufactured, volumetric modular, system-built, and Quonset huts and other reused military buildings[2]). Our further questions about prefabricated housing in the region became the basis for this annotated bibliography. Thus, while this bibliography is one of multiple methods used to investigate these issues, it played a significant role in guiding our research and helped us bring together the diverse perspectives we were hearing from our interviews with building experts in the region and the wider debates that were circulating in the media and, to a lesser degree, in academia. The actual research for each of three sections was carried out by graduate students Lauren Criss-Carboy and Laura Supple.[3] They worked with us to identify source materials and their hard work led to the team identifying three themes that cover intersecting topics related to housing security in Alaska during the pandemic. The source materials collected in these sections can be used in a variety of ways depending on what readers are interested in exploring, including insights into debates on housing security in the region as the pandemic was unfolding (2021-2022). The bibliography can also be used as a tool for thinking about the relational aspects of these themes or the diversity of ways in which information on housing was circulating during the pandemic (and the implications that may have had on community well-being and preparedness). That said, this bibliography is not a comprehensive analysis. Instead, by bringing these three sections together with one another to provide a snapshot of what was happening at that time, it provides a critical jumping off point for scholars working on these issues. The first section focuses on how modular housing figured into pandemic responses to housing needs. In exploring this issue, author Laura Supple attends to both state and national perspectives as part of a broader effort to situate Alaska issues with modular housing in relation to wider national trends. This led to the identification of multiple kinds of literature, ranging from published articles to publicly circulated memos, blog posts, and presentations. These materials are important source materials that will likely fade in the vastness of the Internet and thus may help provide researchers with specific insights into how off-site modular construction was used – and perhaps hyped – to address pandemic concerns over housing, which in turn may raise wider questions about how networks, institutions, and historical experiences with modular construction are organized and positioned to respond to major societal disruptions like the pandemic. As Supple pointed out, most of the material identified in this review speaks to national issues and only a scattering of examples was identified that reflect on the Alaskan context. The second section gathers a diverse set of communications exploring housing security and homelessness in the region. The lack of adequate, healthy housing in remote Alaska communities, often referred to as Alaska’s housing crisis, is well-documented and preceded the pandemic (Guy 2020). As the pandemic unfolded, journalists and other writers reported on the immense stress that was placed on already taxed housing resources in these communities (Smith 2020; Lerner 2021). The resulting picture led the editors to describe in their work how housing security in the region exists along a spectrum that includes poor quality housing as well as various forms of houselessness including, particularly relevant for the context, “hidden homelessness” (Hope 2020; Rogers 2020). The term houseless is a revised notion of homelessness because it captures a richer array of both permanent and temporary forms of housing precarity that people may experience in a region (Christensen et al. 2107). By identifying sources that reflect on the multiple forms of housing insecurity that people were facing, this section highlights the forms of disparity that complicated pandemic responses. Moreover, this section underscores ingenuity (Graham 2019; Smith 2020; Jason and Fashant 2021) that people on the ground used to address the needs of their communities. The third section provides a snapshot from the first year of the pandemic into how CARES Act funds were allocated to Native Alaska communities and used to address housing security. This subject was extremely complicated in Alaska due to the existence of for-profit Alaska Native Corporations and disputes over eligibility for the funds impacted disbursements nationwide. The resources in this section cover that dispute, impacts of the pandemic on housing security, and efforts to use the funds for housing as well as barriers Alaska communities faced trying to secure and use the funds. In summary, this annotated bibliography provides an overview of what was happening, in real time, during the pandemic around a specific topic: housing security in largely remote Alaska Native communities. The media used by housing specialists to communicate the issues discussed here are diverse, ranging from news reports to podcasts and from blogs to journal articles. This diversity speaks to the multiple ways in which information was circulating on housing at a time when the nightly news and radio broadcasts focused heavily on national and state health updates and policy developments. Finding these materials took time, and we share them here because they illustrate why attention to housing security issues is critical for addressing crises like the pandemic. For instance, one theme that emerged out of a recent National Science Foundation workshop on COVID research in the North NSF Conference[4] was that Indigenous communities are not only recovering from the pandemic but also evaluating lessons learned to better prepare for the next one, and resilience will depend significantly on more—and more adaptable—infrastructure and greater housing security. 
    more » « less
  4. The rapid growth of demand in agricultural production has created water scarcity issues worldwide. Simultaneously, climate change scenarios have projected that more frequent and severe droughts are likely to occur. Adaptive water resources management has been suggested as one strategy to better coordinate surface water and groundwater resources (i.e., conjunctive water use) to address droughts. In this study, we enhanced an aggregated water resource management tool that represents integrated agriculture, water, energy, and social systems. We applied this tool to the Yakima River Basin (YRB) in Washington State, USA. We selected four indicators of system resilience and sustainability to evaluate four adaptation methods associated with adoption behaviors in alleviating drought impacts on agriculture under RCP4.5 and RCP 8.5 climate change scenarios. We analyzed the characteristics of four adaptation methods, including greenhouses, crop planting time, irrigation technology, and managed aquifer recharge as well as alternating supply and demand dynamics to overcome drought impact. The results show that climate conditions with severe and consecutive droughts require more financial and natural resources to achieve well-implemented adaptation strategies. For long-term impact analysis, managed aquifer recharge appeared to be a cost-effective and easy-to-adopt option, whereas water entitlements are likely to get exhausted during multiple consecutive drought events. Greenhouses and water-efficient technologies are more effective in improving irrigation reliability under RCP 8.5 when widely adopted. However, implementing all adaptation methods together is the only way to alleviate most of the drought impacts projected in the future. The water resources management tool helps stakeholders and researchers gain insights in the roles of modern inventions in agricultural water cycle dynamics in the context of interactive multi-sector systems. 
    more » « less
  5. Abstract

    La Playa (SON:F:10:3) is an archaeological site in Sonora, Mexico that contains the remains of an extensive preceramic earthen irrigation canal system. Modern floodplain erosion has destroyed the majority of these canals, but geoarchaeological investigations on areas of the system that remain reveal much about this early agricultural technology. Comprehensive dating using accelerator mass spectrometry14C on gastropods, charcoal, and soil humates and single‐grain optically stimulated luminescence (OSL) dating on canal sediments revealed that multiple irrigation systems were used at La Playa during at least two periods during the Early Agricultural period (~750–350 B.C. and ~ A.D. 50–250).14C and OSL age estimates from canals are in agreement with the earliest direct dates on maize from La Playa (A.D. 20–240), indicating that the introduction of maize corresponds to a significant investment in the modification of the floodplain environment for canal irrigation. The late phase of canal use (~A.D. 50–250) occurs before destructive floodplain erosion at the site. This is contemporaneous with local cultural changes, including the development of a new ceramic tradition, changes in burial practices, and changing subsistence strategies. These results demonstrate the utility of the combined14C and OSL approach for dating ancient earthen canals.

    more » « less