Qualitative approach | Quantitative approach | |
GLASOD Map (This study) | Modelling [10, 3] | Sampling programme (indirect methods and fingerprinting techniques [10, 3] |
v Regional (GLASOD map unit) based sediment sources. | v Subcatchment wise sediment sources identified | v Location specific based sediment sources identified. |
v Sheet erosion (top soil removal) dominates in 1DD1 (Kikuletwa) sub-catchment. Not detailed enough to indicate sediment contents and characteristics (organic matter and particle size distribution) | v Sheet erosion dominates in 1DD1 (Kikuletwa) sub-catchment | v Top layer A-horizon or Sheet erosion dominates in 1DD1 (Kikuletwa) sub-catchment. High organic matter content and fine-grained characterize the sediment contents delivered at outlet |
v Mass movement depicted, however, it does not tell which type of mass movement (rill, gully formation, riverbank destruction, or landslides) | v Gully erosion is insignificant | v Insignificant gully erosion process in 1DD1 sub-catchment. Based on aerial photos, few and localized growing gullies in some mountain foot slopes |
v Indirectly captured as terrain definition or mass movement | v Within channel sediment sources | v Lesser extent within channel sediment sources in 1DD1 sub-catchment. Sediment concentrations delivery at outlet though low are sustained even during low flow or dry season v Bank erosion in Ruvu River as monitored at 1DC1 gauging station. Sometimes sediment peaks lead the flood peaks. |