The Tlajinga Canals Revisited: Ground, Aerial, and Space-Based Paleohydrological Prospection in the Teotihuacan Valley, Mexico

Despite its importance to paleoecological models of the Basin of Mexico and theoretical models explaining the origins of sociopoliltical complexity, the study of ancient irrigation in the Teotihuacan Valley has progressed slowly since its isolation as an important variable in the cultural evolution of the valley's societies, and the historical ecology of the region. Barring two studies in the mid-twentieth century, archaeologists have been slow to apply modern archaeometric methods studies relating to irrigation in this region of Mexico. Since June 2013, the Proyecto La Paleohidrología del Valle de Teotihuacan has applied novel and traditional methods in the quest for buried canals, including multispectral satellite imagery, ground penetrating radar, and unmanned aerial structure-from-motion. Test excavations suggest that the previously-identified system is larger in scale than previously thought, showing the remains of long-gone natural and anthropogenic modifications of the land larger than all but one other known irrigation system in the valley. The identification of such an irrigation system suggests that basic assumptions about the valley's paleohydrology and paleoecology may not consider the full suite of strategies available to the ancient inhabitants, highlighting the need for future ecological and archaeological studies in the area. I propose an increased reliance on floodwater irrigation during ancient times than is currently assumed, as well as a strong reliance on amaranth agriculture compared to maize. Furthermore, from such results, it is clear that these methods of remote sensing enjoy success in the quest for paleohydrological data in a heavily eroded, semi-arid environment like the Teotihuacan Valley.