FORMATION AND DISTRIBUTION OF THE VALLEY SIDE GULLIES IN CENTRAL UGANDA

Bob Roga NAKILEZA

Abstract


The dry subhumid area of Central Uganda forms part of the ‘cattle dry corridor’ characterized by relatively low but unpredictable rains, poor resource development, high livestock population and increasing human population densities leading to environmental degradation problems including gully erosion. This paper examines the characteristics of gullies and the main intrinsic and extrinsic variables affecting their spatial distribution in the central drylands of Uganda. A field survey was used. Preliminary studies were done covering two sub counties in the district of Nakasongola, and then more detailed studies narrowed to 2 sub catchments close to Migera town. Ten gullies were sampled for detailed measurements. The spatial distribution of all gully scars were identified in the field and their positions recorded using a Global Position System. This data was imported in Geographical Information System in ILWIS 3.2 environment. Field measurement of gully dimensions (lengths, width and depth) was done and the data used for computing the volume of soil loss from gully erosion. Results revealed that in general land degradation by gullies in this dry sub humid area is an increasing problem, which is mainly attributed to human activities of livestock grazing and movement. The extent and magnitude of erosion by gullies, however, is controlled by soil characteristics and topographic variations. The gullies were largely discontinuous, dominantly of linear pattern and rarely exceeded 2 m depth. There is urgent need to address the problem of degradation by gullies, while taking into consideration the controlling factors, in order to ensure sustainable rangeland management.


Keywords


Dry sub-humid, Gully erosion, Land degradation, Nakasongola, Uganda

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References


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DOI: http://dx.doi.org/10.15551/scigeo.v59i2.279

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