| dc.description.abstract | Groundwater exploitation has considerable potential for boosting water supplies. The
county’s geology and hydrogeology allows for the economic exploitation of the
groundwater resources. Kenya consists of three major rock types namely; volcanic,
metamorphic basement and intrusive rocks, and the sedimentary rocks. The main
groundwater aquifers are closely linked with these three major rock systems. These
groundwater resources are spread over five hydro-geological areas: volcanic rocks area in
the Rift Valley; volcanic rocks area outside of the Rift Valley; the metamorphic basement
rocks area; the eastern quaternary sedimentary rocks area; and the western quaternary
sedimentary rocks area.
Kajiado County is characterized by tertiary volcanics and the Precambrian Mozambican
belt rocks (basement system). The study analyzed the characteristics of boreholes sunk
within Kajiado Municipality and its environs including depth, water struck levels, water
resistivity levels, yield per hour and per day; pumping water levels, specific capacities;
and transmissivity. The objectives of the study included; establishing groundwater
potential by studying the geology of Kajiado Municipality; delineating spatial distribution
of groundwater potential by relating this distribution to structures such as deposition
basins, fresh basement rocks, faults, joints and fractures; identifying gaps in
hydrogeological studies done; and documenting best techniques applicable in the search
of groundwater within Kajiado Municipality and its environs.
The study revealed that there were twenty one boreholes within Kajiado Municipality.
The study area was also found to be of varied ground water potential namely high,
medium and low. Five of the existing boreholes are located in a high potential area while
another five on a medium potential area. Seven boreholes were located in a low potential
area and the remaining four did not strike any and so were dry. Transmissivity readings
were used to determine groundwater potential. The aquifer in the high potential area was
struck between 50 and 80m in depth. Further, it was established that depositional aquifers
were limited to low grounds near the river channels and characterized by the occurrence
of medium ground water potential. High yielding boreholes are located on a fracture
running north south in the project area. The ground water within the area was found to be
mineralized but of good quality according to the WHO standards.
The research also established that the most used geophysical method for exploration in
the project area is the resistivity method as opposed to the seismic method. | en |
