ABSTRACTThis study reports water capacity estimates for four reservoirs within the Classic Maya city of El Perú-Waka’, Guatemala. Combining field survey, soil analysis, and a variety of GIS interpolation methods, it illustrates ways to more fully quantify a challenging resource—water—and its availability using an interdisciplinary approach. This is accomplished by comparing surface interpolation methods for estimating reservoir capacities to demonstrate that most provide reliable estimates. Reported estimates are further enhanced by analyzing internal reservoir soil morphology to better understand and quantify formation processes and refine estimates from field survey. These analyses document a multiscalar organization to water management within the Waka’ urban core that likely ran the gamut from individuals up to civic and state institutions. Although intricacies remain to be fully elucidated, this example offers an alternate path to theorizing about water management practices from traditional binary approaches.