International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004
Arable land per segment/Imagatte
120
100
80
Area of arable land
- (ha)
32003
Figure 2: change in arable land
Table 2: Land use cover statistics
Data source Ground [Landsat |Air
survey image |photo
Year 2003 1989 1969
Geog. area (ha) 7000| 8404; 8373
Arable land (ha) 5748| 3516 1092
Wood/grassland
(ha) 2440 5574 7677
% Arable land 82 42 13
% Wood/grassland 35 66 92
Impacts of Land use cover change
As land use changes from forest to rural built-up
lands, urban lands and subsistence agriculture, surface
runoff increases while surface and groundwater
quantity and quality deteriorates. The effect is
manifested in reduced natural recharge, reduced
stream flow and elimination of wet lands. Currently,
there is a steady recognition that surface and
groundwater sources are declining. River Njoro no
longer flows throughout the year. Boreholes are drying
up, especially at Egerton University where 4 out of 11
have dried up. Reduction in the water quantity in Lake
Nakuru has been blamed on deforestation in the Mau
range which is the source of rivers Njoro and Lamriak,
the main rivers flowing in the lake. Agriculture has
moved up the slopes and in the riverine areas as shown
in figure 7. There is no forced fallow any longer even
as land loses fertility. The practice of continuous
cultivation is impoverishing the soils. Sheet and rill
erosion is observed when it rains and gullies are
beginning to develop along some of the farm tracks.
Deforestation and break down of the soil conservation
structures which were established by the settler
farmers has led to increased soil erosion and
sedimentation of lake Nakuru.
Conclusions
The use of remotely sensed data showed that eastern
Mau has had a significant change in land use cover
over the last 40 years. The temporal images showed
the pre-change and post-change cover types. The
$b
Segments
26 29 30 31 34 42
30a 34a 42a 42b
BH 1989 (11969
landsat image of 1973 clearly showed rich vegetation
cover. Deforestation, land fragmentation, cultivation
of wetlands and rapid increase in human settlements
have had negative impacts on water sources resulting
in reduced stream flows and water shortages.
Groundwater sources continue to dwindle,
necessitating the sinking of new and deeper wells and
boreholes in places like Egerton University and farms
around Njoro. Inadequate or lack of data on
hydrology, meteorology, biodiversity and land use in
eastern Mau inhibits proper development and
management. The study showed that remotely sensed
data can provide information for effective routine
tasks related to environmental inventorying and
monitoring. The results from manual interpretation
closely matched those of supervised classification of
the landsat image shown in figure 9. Since manual
interpretation is cheaper, its use will go a long way in
providing data for managing the Mau complex which
is an important water tower in Kenya by remotely
sensed data and hence enable sustainable development
of resources in this part of Kenya.
LEGEND NUT
7X [Take Nakure Water
calchment boundary
Figure 3: The study area is shown in red line
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