Use of Digital Elevation Models in Tropical
Rain Forest Basins to Extract Basic
Hydrologic and Land Use Information
G. Arturo Sánchez-Azofeifa
ASSESSMENT of environmental damage due to deforestation and its impacts on evapotranspiration, infiltration, and runoff requires better climatic, geomorphological, and geographical databases. These databases will require new technological tools based on remote sensing, spatial statistics, and nonparametric statistics for quantitative impact analysis. These observational and analytical methods are not only important for assessing current environmental deterioration trends but may also have the potential to clarify future impacts of land use changes on the environment.
Two of these tools—the generation of land use information from satellite images and the extraction of topographic characteristics from digital elevation models (DEMs)—have proved to be important in a wide variety of fields (Sader and Joyce 1988; Sader, Powell, and Rappole 1991; Vesrtappen 1977). These can be especially helpful in studying impacts of land use changes on water resources management.
Topographic properties extracted from DEMs, such as drainage networks and catchment boundaries, can be related to different hydrologic and geomorphologic characteristics such as sediment erosion, production and transport, streamdischarge characteristics, and climatic patterns (Jenson 1991; Jenson and Domingue 1988; Joyce, Luvall, and Sever 1990; Klingebiel et al. 1987; Levine et al. 1993; Martz and Garbrecht 1992; Sader and Joyce 1988; Sader, Powell, and Rappole 1991; Vesrtappen 1977). Additionally, DEMs can be used in conjunction with GIS as decision-making tools for developing sustainable land use policies in tropical environments where other geographic data is poor or nonexistent. The