Leng, Melani(PhD)Kebede, Seifu2022-03-242023-11-182022-03-242023-11-181990-06http://etd.aau.edu.et/handle/12345678/30821The Bishoftu Crater Lakes, located on the western shoulder of the main Ethiopian Rift can provide a sedimentary record, which has regis!ered the changes in the balance between precipitation input and evaporative water loss. However, groundwater fluxes may reduce sensitivity of the lakes to a change climate. In order to test the possibility to use the lakes as paleohydrometers, the modem balance between precipitation, evaporation and groundwater flux has been determined. In the Bishoftu area where hardrock form the terrain geochemical and isotope mass balance has been found suitable to be used to constrain the water budget. Although stable isotopes of oxygen and deuterium as aid in quantifying water balance of the lakes have limitations due to the lack of measurement of environmental parameters such as h, E, I1E ; the same approach has been found appropriate for this study. The varying hydrology of the Bishoftu crater lakes has provided a suitable base for determining water budget using stable isotope method without reverting to the measurement of environmental parameters. Accordingly the lakes have been found suitable for quantitative isotope hydrology and quantitative reconstruction of paleoclimate from lake carbonate records. Of the existing five crater lakes, lake Hora, lake Arenguade and lake Kilole are least affected by groundwater outflow while lake Babogaya and lake Bishoftu are more influenced by groundwater outflow. The hydrology of lake Kilole is recently influenced by the diversion of the Mojo river into the lake. Geochemical mass balance results show that lake Arenguade might be affected by geothermal water flux . Of all crater lakes, lake Hora is therefore selected as the most suitable for paleoclimate studies.enHydrologicalHydrochemicalThesis