Water Source

Sampling points

Geology at Sampling Site

Transect 1 (Western Transect)

Transect 2 (Central Transect)

Transect 3 (Eastern Transect)



River Kisian originate from the Maragoli Hills and contribute along its length to the groundwater system. The hills composed of granite and lowlands recent granitic soils

No river along this transect but all springs located here convert into small streams during heavy rain. Andesite, phonolite, murrum, black cotton soils and grit forms the cross-section from the hills to Lake Victoria (no river samples)

River Kibos/Nyamasaria originate from the Nandi Hills and contribute to groundwater balance on the eastern transect. Nandi hills dominated by granite, lowlands by black cotton soils and the Lake shore by grit



No spring along this transect.

Four sampling springs and all are located on unconsolidated phonolitic rocks and murram. (48 samples)

A single spring located at the contact between grit and phonolite in Manyatta. Small springs sprout during rains.

Shallow Well


Shallow wells are located along this transect on phonolitic boulders and murram.

Wells along this transect are very shallow, less than a meter especially in Obunga. Murram (lateritic soil) is the main formation. (12 samples)

Recent black cotton soils dominate the Kano plains. High clay content within the Kano plains lenders shallow well construction difficult. However, a few wells are located on the upper reaches of this transect in Kibos and Kajulu.



None on this transect. Shallow depths to the solid basement rock renders drilling not to be cost effective.

Very productive boreholes between the contacts of the andesites and phonolite. (12 samples)

Very productive boreholes with the Kano plains where the drilling penetrate through the black cotton soil.



Shoreline geology is characterised by clay and grit

Lake Shoreline geology composed of grit (No sample)

Grits on the Lake shoreline.