Sustaining Lake Levels in Lake Nakuru, Kenya: Development of a Water Balance Model for Decision Making
Marion W. Jenkins; Stephen McCord; Joseph Edebe
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Global Livestock CRSP, University of California- Davis
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Abstract: Fluctuations in Lake Nakuru’s water level, particularly since the mid-1980s have been a source of significant concern for the sustainability of the lake’s unique ecosystem. To improve collective understanding of lake level fluctuation and drying, and to explore impacts of regional population growth, increasing water extraction, and land use changes, a preliminary water balance model of the lake was developed and initial analyses undertaken. Direct rainfall is the largest inflow to the lake, followed by tributary discharges and groundwater seepage. The lake’s hydrologic balance appears to have changed substantially since the 1970’s, with the proportion of water entering the lake rapidly as surface water – rather than perennially as groundwater – having increased, causing lake level and salinity to fluctuate more rapidly. This change is linked to an apparent increase since the 1970’s in surface water runoff at the expense of groundwater recharge in the lake’s River Njoro and other upstream watersheds. A declining groundwater table has the greatest negative impact on the sustainability of lake levels. The present situation calls for major efforts to improve hydro-meteorological monitoring and data management for the greater Lake Nakuru area with a priority on groundwater monitoring and institutionalization of these activities as essential governance rather than as piecemeal, short-lived projects.