University of Twente Student Theses


Water Efficiency and its effects in Lake Naivasha, Kenya

Veenvliet, Martin (2014) Water Efficiency and its effects in Lake Naivasha, Kenya.

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Abstract:Water is interconnected with society, economy and ecology; this is not any different in the case of Lake Naivasha. The interconnection between commercial water abstractions, the economy of water, the domestic water usage and the ecology of Lake Naivasha were assessed. Through three different surveys, one of them focussing on water efficiency on commercial farms, two of them focussing on domestic water efficiency were developed. These surveys were conducted on several places around Lake Naivasha and were later analysed. The analysis of commercial abstraction focusses on the water footprint of a crop and the irrigation system performance efficiency (ISPE). Domestic water efficiency focusses itself on the current water infrastructure in the settlements around Lake Naivasha. The Blue water footprint was found to be about 1200 m3/kg for a crop in a hydroponic, a 1600 m3/kg for a crop in a greenhouse and 1900 m3/kg for a crop in an open-field based farming system. The green water footprint was only assessed for the open-field based farming system and was calculated to be around 1700 m3/kg. The Irrigation System Performance Efficiency (ISPE) was calculated for the different scenarios and it was found to be that the only notable loss form abstraction to irrigation is the reservoir evaporation. Therefore the area of the reservoir is important, as a bigger reservoir means a bigger evaporation. The water application rates were found to be around 90% for hydroponics, which means 90% of the applied water is actually used by the crop and about 20-40% for greenhouse based farms. Another advantage of the hydroponic is the 40-50% recycling efficiency, which means that 40% of the total used water is actually recycled from the previous cycle. The results of the surveys were also analysed for non-water parameters, including economy, human rights and biodiversity. Every water efficiency improving measurement was researched for costs and benefits. These include the investment costs, maintenance costs, chemical costs and improved yields. It was found that in the ideal situation farms would transfer to Hydroponics, as the next step, aeroponics, is not possible in the current Kenyan infrastructure. For domestic water usage it was found that not all UN-guidelines are met. Furthermore water infrastructure seems to lacking in most areas around Lake Naivasha. The current situation is that people often have to drink water from boreholes, which is high in fluorides. This causes dental fluorosis amongst most of the population around Lake Naivasha. The biodiversity and water quality were analysed through the help of experts and were mainly focussing on the linkage between water hyacinth coverage, Chlorophyll ‘a’ and nutrients. Furthermore the Water Quality Index for Biodiversity was calculated which proofed that the water quality between 1967-2002 was marginal for Lake Naivasha. The best investment, both economically and based on water usage, would be for farms to invest in a hydroponic. For the domestic water usage it is recommended to developed water infrastructure in the settlements around Lake Naivasha.
Item Type:Essay (Bachelor)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering BSc (56952)
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