Water Resources Studies in Headwaters of the Blue Nile Basin: A Review with Emphasis on Lake Water Balance and Hydrogeological Characterization

Water

Jan Nyssen¹  Ann Van Griensven²  Enyew Adgo³  Mekete Dessie⁴  Mulugeta Azeze⁴  Marc Van Camp⁵  Kristine Walraevens⁵  Fenta Nigate⁶  Alemu Yenehun⁶  AshebirSewale Belay⁶ 

[1] Department of Geography, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent, Belgium;Department of Hydrology and Hydraulic Engineering, Faculty of Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium;Department of Natural Resource, Bahir Dar University, P.O. Box 79, Bahir Dar 6000, Ethiopia;Faculty of Civil and Water Resources Engineering, Bahir Dar University, P.O. Box 430, Bahir Dar 6000, Ethiopia;Laboratory for Applied Geology and Hydrogeology, Department of Geology, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent, Belgium;School of Earth Sciences, Bahir Dar University, P.O. Box 79, Bahir Dar 6000, Ethiopia;

关键词: Lake Tana Basin;    water balance;    hydrogeology;    aquifer;    recharge;    research gap;   

DOI  :  10.3390/w13111469

来源: DOAJ

【 摘 要 】

The Lake Tana Basin, comprising the largest natural lake in Ethiopia, is the source and the uppermost part of the Upper Blue Nile Basin. In this review paper, research papers, mainly on the rainfall-runoff modeling and lake water balance, and on the hydrogeology, have been reviewed. The earlier water balance estimation attempts used simple conceptual and statistical approaches and calculate on a monthly timescale. More recent research has been using advanced semi-physically or physically based distributed hydrological models. Accordingly, mean annual precipitation over the lake was estimated in the range 36.1–53.1%; lake evaporation at 45.3–57.5%; river inflow (all gauged and estimated ungauged) at 43.6–63.9%; and river (lake) water outflow at 0–9.2%. With the few isotope studies, groundwater inflow and outflow are found insignificant. Different studies had estimated groundwater recharge, ranging from 57 mm to 850 mm. The basin has a heterogenous aquifer system consisting of different volcanic rocks and alluvio-lacustrine sediments. Generally, groundwater with low TDS, Ca–Mg–HCO₃ type, isotopically relatively enriched, and high TDS, Na–HCO₃ type, isotopically relatively depleted, water types have been identified. In this paper, major research gaps such as aquifer hydraulic characterization, surface-groundwater interaction, groundwater flow and groundwater balance have been identified. Hence, future research shall focus on the groundwater resources, so that existing surface water studies are updated and future water usage options are explored.

【 授权许可】

Unknown