Abstract:
The Lake Victoria Basin is facing major environmental challenges that have caused considerable
hardship for the population depending on it for their livelihoods and have also reduced the
biodiversity of the lake's flora and fauna. Deforestation coupled with bad agricultural practices
has persistently exacerbated the problem of land degradation in the basin and sedimentation in
the lake. Assessment of land degradation hazard is considered essential for soil conservation
plans in the basin for sustainable development. The objective of this study was to identify and
map the extent and severity levels of land degradation caused as a result of soil erosion by water
on the Kenyan section of Lake Victoria basin (LVB) in order to support informed decisions for
prioritizing and combating land degradation menace in the basin. We used Geospatial techniques
and empirical soil erosion modeling techniques, mainly the Revised Universal Soil Loss
Equation (RUSLE) Model that looked at five key soil erosion control parameters: vegetation
cover, rainfall erosivity, slope factor, soil erodibility, and population density data as input
variables. The results from modeling were subjected to field assessment in one of the identified
hot spots in Bolo area in Kisumu County. Major erosion hotspots were found to be areas around
Mumias, Bunyore, Kisumu, Kendu Bay, Ahero and south-western parts of Homa Bay. This study
revealed that the lead contributing factor to soil erosion in the basin was soil erodibility
component followed by rainfall erosivity, vegetation cover management, population density and
finally slope factor. The study recommends comprehensive catchment level degradation
assessment to be undertaken and prioritise the most affected areas. |
