Soils
Typical tropic red soils (Latosols) are located in the mountain areas at high altitudes. They have a high clay content, a thin, but fertile, humus layer and a distinct aggregate structure. These characteristics make them resistant to soil erosion.
The soils of the gentle to sloping slops of the middle and low altitudes are covered by light red soils. There also a lot of patches of grey soils (Gleysols, "vlei soils").
Shallow, stony soils are located on the steep slopes around the channels. The flat areas around the channels are swampy.
Soil erosion and mass movement are one of the major problems in the catchment.