In 2017, Jorge welcomed me to the headquarters of Costa Rica’s underground water agency. His supervisor had asked him to show me “the model” at work. After many years of fieldwork on water issues, I had already been introduced to many models: the mathematical model to calculate extraction rates, two different pieces of software that model aquifer flow, the regulatory model Costa Rica’s agency follows, and sponges as a preferred physical model to conceptualize aquifers. And yet, Jorge and his supervisor referred to this one as el modelo, the model.
After walking down a zigzagging hallway, we eventually entered an office where three unused desks were stored. In this unremarkable bureaucratic context, illuminated by fluorescent lighting, the model rested atop an old desk, a temporary pedestal. The model consisted of a transparent plastic structure simulating a vertical slice of the underground that revealed its stratigraphic architecture. It resembled a skinny terrarium with layers of pulverized rock of different textures, colors, and thicknesses. A number of transparent tubes penetrated to different depths, each representing a well. Larger indentations stood for rivers and lakes, and on one side there was a deeper section that, as Jorge explained, represented the ocean. […]