Digital Terrain Analysis Approaches for Tracking Hydrological and Biogeochemical Pathways and Processes in Forested Landscapes

Abstract

Digital terrain analysis (DTA) comprises a set of tools that use digital elevation models (DEMs) to model earth surface processes at a range of scales. DEM and its derivatives are part of a larger set of digital terrain models (DTMs) used in various fields to model the flow of energy and materials across surfaces. The ubiquity of DTMs in the hydrologist’s toolkit has led to the widespread use of terrain attributes such as slope and upslope contributing area to characterize the way water and associated nutrients move across landscapes. Algorithms to compute terrain attributes are now programmed into all commercial Geographic Information System (GIS) software (e.g., ArcGIS, Idrisi) and with a push of the button users can map patterns of potential surface hydrological flows. While the derived layers always look visually stimulating, field hydrologists have often raised the question: are DTMs often merely interesting spatial patterns with not much relevance to predicting actual hydrological behavior? This synthesis critically answers this question by discussing the relevance of DTA for practicing forest hydrologists in the twenty-first century.