Water, salt, and heat in raised field agriculture: Using hydrologic modeling and thermal imagery to investigate soil drainage and temperature dynamics

On the north coast of Peru in the Casma Valley exist relict raised agricultural field systems dating to the Late Intermediate Period Chimu Empire (ca. 1300 – 1470 CE). While similar in many ways to other inland and coastal raised fields in South America, these fields are relatively unique in climate, weather patterns, and layout. The topography and hydrology of the Casma Valley provide clues on how these fields operated and why they differ from the regional norm. This paper reports satellite and drone-based aerial reconnaissance results used to collect multiscalar data for flow modeling and thermal photogrammetry. Flow modeling methods are compared to determine the best way to gain insight into surface hydrology using only elevation data, and thermal photogrammetry is used to analyze temperature dynamics in the raised fields. These data results provide insight into the function of the field system and its unique field morphology.