| dc.description.abstract | Occurrence of groundwater in the basement complex terrain of Makueni County,
Eastern Kenya is controlled by secondary porosity developed through weathering, fracturing
and cracking of the bed rocks. Makueni falls in semi-arid region that is characterised by
erratic rainfall. Surface water from a very few rivers is inadequate and the only option to
supply both human and animal population is groundwater. To avoid the ever common
incidences of borehole failing to yield any water or drying up soon after commissioning,
groundwater mapping is paramount. In this study, remote sensing (RS) and Geographical
Information System (GIS) techniques have been used to identify and map groundwater
potential zones using rainfall, drainage and drainage density, lineament, geology, soil texture,
slope and land cover. These thematic layers were selected for groundwater mapping based
on literature and geophysical investigations and data appropriately weighted in a modified
DRASTIC model based overlay scheme. Land cover was derived from Land sat imagery
classification with lineament density being obtained from the same satellite imagery/product.
The Geospatial evaluation produced a groundwater potential map in which the study area was
characterized into zones; very good, good, moderately good and poor. The map showed that
the central and eastern regions of Makueni County are the most suitable for groundwater
exploitation. | en_US |
