ABSTRACT
This chapter reviews briefly some background ideas concerning tropical fluvial systems, including the effects of tectonic and climatic stability which may influence such systems. It focuses on the development of alluvial fans in a tropical environment. Sediment transport and deposition by tropical rivers have received little attention, despite the number and variety of depositional environments found in the equatorial zone. Although the geomorphologist must appreciate the probable effect of such climatic changes, it raises the question of the time-span necessary for landform development or landscape modification. The pattern of landscape changes resulting from periodic fluctuations defy generalization. Sediments on humid fans are deposited entirely by fluvial processes and strong interrelationships exist between the textural trends of the sediments, fan gradient, and progressive distance downfan. Alluvial fans in Costa Rica illustrate fluvial depositional landform development in a tropical environment, within a tectonically active setting.
