Pre-Feasibility Study Report of the potential hydropower project at the Mandaya site in Ethiopia, carried out as part of Module 5 (Pre-Feasibility Studies of Three Proposed Hydropower Project Sites) of Phase I of the Eastern Nile Power Trade Program Study, implemented by ENTRO from 2006 – 2008. The main topics considered include: a review of previous studies, general hydrology, flood studies, sediment analysis, reservoir and power simulation (using RAPSO model), effects of the dams downstream, geology (rock outcrops around the dam site and its vicinity, geomorphology, discontinuities/fractures/joints, seismic hazards, and other essential geotechnical evaluations), proposed design of the dams and power station (the dam, spillway, intake structures, penstocks, power house, tailrace, switchyard, etc.), electro-mechanical equipment (turbines, generators, transformers), transmission system, access road bridges, cost estimates, construction program, environmental impacts, CO2 emission savings, economic and financial analysis.