Hydrodynamics of Selected Ethiopian Rift Lakes
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Date
2010-06
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Addis Ababa Universty
Abstract
The Main Ethiopian Rift Valley lakes suffer from water level
fluctuations due to several natural and anthropogenic factors. Lakes
located at terminal positions (no surface water outflow) are highly
affected by the fluctuations. These fluctuations are disturbing the
stability of the ecosystems, putting very serious impacts on the lives
of many animals and plants around the lakes. Hence, studying the
hydrodynamics of the lakes was found to be very essential. The
main purpose of this study is to find the most significant factors that
contribute to the water level fluctuations and also to quantify the
fluctuations so as to identify the lakes that need special attention.
The research methodology includes correlation and least squares
regression of lake levels on rainfall, discharge and evaporation,
multi-temporal satellite image analysis and land use change
assessment. The results of the study revealed that much of the
fluctuations in the lake water levels are caused by human activities
especially for the lakes in the Central Ethiopian Rift. Lakes Abiyata,
Chamo, Ziway and Langano are declining while Abaya and Hawassa
are rising. Among the studied lakes, Abiyata is drastically reduced in
size (about 28% of its area in 1986) due to both human activities
(most dominant ones) and natural factors. The other seriously
affected lake is Chamo with about 11% reduction in its area
between 1986 and 2010. Lake Abaya was found to be relatively
stable during this period (showed only a 0.8% increase in its area).
Keywords: Correlation, fluctuation, hydrodynamics, lake level,
Landsat satellite images, land use change, least squares
regression.
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Keywords
Correlation, Fluctuation, Hydrodynamics, Lake level, Landsat satellite images, Land use change, Least squares regression