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Geologic Constraints On Rain-Fed Qocha Reservoir Agricultural Infrastructure, Northern Lake Titicaca Basin, Peru, Nathan M. Craig, Mark Aldenderfer, Paul Baker, Catherine Rigsby, :Luis Flores Blanco

Nathan M Craig

This paper reports new data on qocha ponds from the Rio PucaraeAzángaro interfluvial zone, northern Lake Titicaca Basin, Peru. Qocha are a little known form of Andean agriculture that developed around 800e500 B.C. and remain in use today. Prior estimates suggested that in the study area, there were more than 25,000 qocha. While most Andean sunken beds are excavated to reach groundwater, qocha are rain- fed ponds. How these rain-fed ponds functioned has been an open question, but one that is answered in part by research presented in this paper.We suggest that a thick impermeable stratum of clay that was …