Print Email Facebook Twitter Flow regime change in an endorheic basin in southern Ethiopia Title Flow regime change in an endorheic basin in southern Ethiopia Author Worku, F.F. Werner, M. Wright, N.G. Van der Zaag, P. Demissie, S.S. Faculty Civil Engineering and Geosciences Department Water Management Date 2014-09-30 Abstract Endorheic basins, often found in semi-arid and arid climates, are particularly sensitive to variation in fluxes such as precipitation, evaporation and runoff, resulting in variability of river flows as well as of water levels in endpoint lakes that are often present. In this paper we apply the indicators of hydrological alteration (IHA) to characterise change to the natural flow regime of the Omo–Ghibe Basin in southern Ethiopia. Little water resource infrastructure has been developed in the basin to date, and it is considered pristine. The basin is endorheic and is the main source of flow to Lake Turkana in the East African Rift Valley. The water level in Lake Turkana shows significant fluctuation, but increase of its level can be observed over the past 20 years. The reasons are currently not well understood. Of the five groups of hydrological characteristics in the IHA (magnitude, timing, duration, frequency and variability), only those related to magnitude were found to show significant trends, with the main trend being the increase of flow during the dry season. This trend was not reflected in climatological drivers such as rainfall, evaporation and temperature (which shows a positive trend), but rather is attributed to the substantial changes in land use and land cover in the basin. The change in the basin hydrology is apparent mainly in the more humid part of the basin. The significant shift from forest and woodland to grassland and cropland results in a decrease of actual evaporation and subsequent increase in (dry season) runoff. The long-term trend of the increasing levels in Lake Turkana are related to these trends in dry season flows, while shorter-term fluctuations of the lake levels are attributed primarily to anomalies in consecutive wet and dry season rainfall. To reference this document use: http://resolver.tudelft.nl/uuid:eee34e59-33a4-4e9c-ac15-191b0d7677f8 DOI https://doi.org/10.5194/hess-18-3837-2014 Publisher European Geosciences Union ISSN 1027-5606 Source http://www.hydrol-earth-syst-sci.net/18/3837/2014/ Source Hydrology and Earth System Sciences, 18, 2014 Part of collection Institutional Repository Document type journal article Rights © 2014 The Author(s)CC Attribution 3.0 License Files PDF 309738.pdf 2.99 MB Close viewer /islandora/object/uuid:eee34e59-33a4-4e9c-ac15-191b0d7677f8/datastream/OBJ/view