Eutrophication Prognosis and Realities for Lake Naivasha: Causes, Effects and Management Strategies

Abstract

Lake Naivasha is the only freshwater (<5000 s/cm) Lake in Kenya’s Rift Valley. The Lake is continually becoming more eutrophic due to environmental degradation and anthropogenic organic pollution and nutrient loading from intensive agricultural practices on the Aberdares and Kinangop catchments. Phytoplankton biomass shows a significant increase with time over the past decade. Some positive correlation between algae biomass, phosphorus and nitrogen dynamics have been discerned. There is overwhelming evidence of reduced Phytoplankton species diversity over the years which may be correlated with soluble reactive Phosphorus (PO4 –P) and soluble nitrates. It is predicted that with the current increase in population and agricultural practices, by the year 2010, the Lakes nutrient levels and eutrophic status will be more than trebled. The possible management solution would be rational management of agricultural land use.