TROPICAL SOIL PROPERTIES AND HILLSLOPE HYDROLOGY

Soils form the interface between the atmosphere and the sub surface and soil properties have a large influence on the partitioning of rainfall into runoff and aquifer recharge. In many tropical watersheds detailed information on the distribution and nature of soil properties is scarce making it difficult to identify correct parameters for modeling the hydrologic characteristics of these complex watersheds. The generally accepted view is that tropical soils are deep, very strongly weathered, have high clay contents and little organic matter. A study of soils in several drainage basins within the Chagres watershed have shown a diverse range of soils, with those conforming to the general view in the minority. Hillslope processes, in particular mass movement and tree fall, result in a complex spatial pattern of soil characteristics including soil hydrologic properties. These processes must be accounted for in attempts to model the hillslope response to precipitation events.