Water, Salt, and Heat in Raised Field Agriculture: Using Hydrologic Modeling and Thermal Imagery to Investigate Soil Drainage and Temperature Dynamics

Abstract 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 a novel method of low-cost, accessible thermal photogrammetry is proposed and tested. These data results provide a landscape-oriented perspective on the Casma River floodplain and help us to understand the short and long-term effects of raised field agriculture in this area.