GROUNDWATER POTENTIAL OF GWASI AREA
This study area is found in Gwasi which is a town in Suba district within Homabay County. It is
boarded by Migori district to the south and Homabay district to the east and the remaining
boundaries are the Lake Victoria water body. Its boundaries are defined by Easting’s 621000 to
the West and 633000 to the East and Northing’s 9917000 to 9930000 on the topographical map of
Gwasi area, sheet No.129/1. This area covers approximately 80km2. Gwasi town is connected by
roads to Huma mountain reserve, Rusinga islands and the main road to Kisumu city and Kisii town
and water transport is another form of transport. Gwasi is surrounded by major towns like
Homabay and Migori towns. The main purpose of this study is to determine the geology and
ground water potential of the area. Ground water potential in this study area majorly depends on
the structures and its geological formations, as most successful boreholes are concentrated within
the contact zone between the tertiary nephelinite and the alluvial deposits, and also close to the
fault line.
The borehole data used in this project were acquired from Dr. Z.N Kuria, topographical map from
the Geology Department, University of Nairobi and scanned topographical, geological maps
acquired from Mr. Atonya. The geological map was digitized using ArcGIS software,
transmissivity data processed using Arc map and surfer 11 used in constructing piezometric levels.
Ground water in this area can only support domestic use due to the transmisivity rate which is
7.5m3/day.