Geological structural controls on the groundwater flow into the Lake Naivasha and the risks of over exploitation on the future of the lake

Abstract

Lake Naivasha has a tremendous importance to its environs as a source of freshwater. The lake plays a key role in providing a habitat for a wide range of aquatic flora and fauna. The lake, together with its associated aquifers, provides water utilized for irrigation, geothermal drilling activities, watering of livestock, and domestic use among other uses. Over the past few decades, the lake levels have drastically reduced due to increased water abstractions from the lake raising concerns over the sustainability of the lake for the various activities it supports. Over the past few decades, the lake levels have drastically reduced due to increased water abstractions from the lake basin raising concerns over the sustainability of the lake for the various activities it supports. Environmental science in Australia (1992) in an E.I.A. study in the area estimated that about 59*10⁶m³/yr of water is drawn from the lake, with the estimated outflow value (seepage to groundwater) being 34*10⁶m³/yr (McCann, 1974). Lake Naivasha is considered an integral part of the groundwater flow system all the flow patterns between the lake and the groundwater system are not well understood. A lateral underground flow to the north and southwards is, however, certain with the waters providing recharge for Lake Elementaita and Lake Magadi respectively. The need to understand the geological controls responsible for this flow, both from the lake to the aquifers and also across the aquifers themselves is vital so as to provide the basis for exploitation of this resource.