Characterization of slope morphology and processes and assessment of their implications to slope development dynamics in Central Bunyoro Hills in Hoima District
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In response to the paucity of data on slope morphology, slope processes and slope development in Central Bunyoro hills in mid-western Uganda, this study has generated a large amount of data on relationships of different variables that influence slope morphology and processes as well as information on the factors that determine the processes and the influence of human activities to slope processes and slope development. The study aimed to characterize the dominant morphological features in these hills, and establishing the dominant slope erosion processes, weathering processes and the significance of these features and processes on overall slope development in the region. In the study, transects were drawn from the lowest points usually the valley bottom to the top most part of the hill. Transect walks were made along the transects drawn, during which observations, measurements and recording of data and information on various variables and processes were made. The study involved carrying out measurements on a number of parameters like the sizes of gullies and rills by measuring their depth, width and length. Measurements were also undertaken on soil depth and slope length, which were all done using a tape measure. Furthermore slope gradients were measured using a clinometer and topographic maps. The landscape in the region is characterized by landforms in three stages of development (youthful, mature and old) just as described by the American worker M.W.Davis with average gradients of about 11o. In some areas mostly in Kitoba sub-county the highlands are still very steep with highlands rising to the height of over 1500m above sea level and this landscape covers about 25% of the total land area. The landscape with mature slopes forms the biggest portion of the land, with hills rising to the height between1200m and 1480 m. This kind of landscape with hills in the mature stage almost makes up over 50% of the entire landscape. This surface covers most parts of Kigorobya and western parts of Kitoba sub counties. The landscape has been assumed to be in the peneplain stage, which is almost reduced to a gently sloping surface of less than 4.5o or nearly flat surface with slopes rising to less than 1200m above sea level. This is mostly found in the North and western parts of Kigorobya Sub County and covers over 25% of the entire surface of these hills. The major processes occurring and affecting the hillslopes of Central Bunyoro include erosion especially in form of rainsplash, overland flow, and channelised flow in form of rills, gullies, and rivers. Other processes include mass movement in form of slides and rock falls as well as creep, weathering processes and deposition of the eroded materials downslope. The major factors that influence slope processes in study area include: slope angle, rock properties, climate, variation in vegetation cover and, drainage. Human activities have a strong influence on the slope processes. Human activities have accelerated the slope processes especially erosional and significantly impacted on the trends in slope development in the region. More studies are required to advance further the utility of the findings of this study. In particular there is need to investigate further the actual rates of weathering and erosion and how the dynamics of these processes help to interprete the rate of slope development in this part of the humid tropical world.