Investigation of physical and bathymetric characteristics of Lakes Abaya and Chamo, Ethiopia, and their management implications
The purpose of this study was to investigate the physical parameters of Lakes Abaya and Chamo in the Ethiopian rift lakes system, including such physical characteristics as depth, water resources capacity, hydrology, water balances, and impacts of water use and degradation of their watersheds. These parameters have not previously been studied for these two lakes to any significant extent. This study describes the bathymetry survey undertaken for these two lakes, and the morphometric characteristics derived from it. This study is part of a research project developed to provide further details on such parameters as hydrology, water quality, sediment inflows and deposition, lake hydrodynamics and consumptive water uses. The bathymetric survey was conducted, utilizing a combination of global positioning system (GPS) and echo sounder. To calculate the morphometric characteristics, the background lake map was digitized, and the surveyed primary data were developed as digital values. The digital values were interpolated, generating grids of the elevation surface. The elevation area and elevation volume curves (capacity curves) of the two lakes were developed from the digital values, describing the water resources capacity of the lake water basins. The results of this study increase our understanding of the water resources of these two lakes, as well as provide better understanding of their vulnerability to human activities because of their shallow depths. Immediate application of the results, as a basis for continuation of this study, also is highlighted.