1 Spatial Modelling of the Terrestrial Environment - Georeferencial

166 Spatial Modelling of the Terrestrial Environment
Figure 8.2 Erosion for the three decads of April 1998
substantial rainfall, overland flow and erosion in the catchment itself. The northern region
of the Lake Tanganyika catchment centred on Rwanda and Burundi suffered severe erosion
and was a likely source of lake sediments. When it is considered that slopes are high in
these regions, that they tend to be densely populated, and thus vegetation cover is being
reduced by human interference, it goes a long way to explaining the high erosion predicted
in these regions. Thus erosion is largely restricted to the mountainous regions; however, not
all mountains produce erosion, presumably because some possess high vegetation cover.
Though we only have results for a single month, these erosion estimates suggest that there
are a few key regions in Rwanda, Burundi and the Democratic Republic of Congo that are
prone to erosion. Some of these regions have already been deforested and degraded (i.e.,
those in Burundi) and have the potential to produce significant sediment input to the lake.
In these areas the model suggests that alleviation measures could be considered. However,
before this is done, the model results need further evaluation and validation. It is interesting
to note that a number of the regions of highest sediment yield are located in areas that are
cloud covered throughout much of April, so vegetation cover estimates in these regions
are uncertain and thus the erosion results should be treated with caution. This problem