Geography Reference
In-Depth Information
II.6. Organization Diagram of Integrated Parameters in the GIS
Figure 8. Integrated parameters (Rainfall, lineament density, Geology, Slope, Drainage
density) and their percentage weights.
III.
R
ESULTS AND
D
ISCUSSION
Integration of the weighted parameters into a GIS platform infers a
groundwater potential map with five potentiality classes in the study area
ranking from very high potential groundwater zones to very low. It is noted
that, high potential zone is located in the South of Sabodala mining region
contrasting to the northern part where groundwater potential is low due to
decrease in rainfall and type of lithology formations made up of granites
essentially. The output map (Fig. 9) resulting from GIS combination of
different parameters (rainfall, lineaments, geology, slope, drainage network)
shows a map of five potential aquifer zones (Fig. 9) ranging from zones with
very high potential to zones with very low potential. Thus about 5% of the
investigated area has a very good potential. These zones are mostly found in
the south of the area situated in the southern part of the Gambia River
watershed between 1250 to 1150mm isohyets and on the main transcurrent
zone (MTZ). However, zones presenting a very good potential are also noted
in the sector located between isohyets 1150 to 850 mm, which are isolated
zones and can be found on the south part of the Saraya's granite (south and
east of the Saraya city), south of Kanouméry village and its immediate
surroundings. Very good potential is also localized in the volcano-sedimentary
