HYDROLOGICAL ANALYSIS OF TANA BELESE HYDROPOWER PROJECT IN ETHIOPIA

Abstract

In this study the hydrological Analysis of, the feasibility of hydroelectric power generation from Lake Tana, in the area of Tana Belese , which was under constructed by the state government of Ethiopia in the Amhara Region (north western of Ethiopia),about 150km to the Bahirdar town, for hydropower & irrigation purpose is investigated. Tana Belese is one of the multi-purpose projects currently under way to develop the resources in Ethiopia. Lake Tana is a natural reservoir for the Blue Nile River which has huge potential for Hydropower and irrigation development. Water resource development is being encouraged by the government to stimulate economic growth and reduce poverty. Hydropower converts the energy in flowing water into electricity. The quantity of electricity generated is determined by the volume of water flow and the amount of "head" (the height from turbines in the power plant to the water surface) created by the dam. The greater the flow and head, the more electricity produced.So the study has shown the estimation of the Annual energy of Tana Belse hydropower plant in MWh. The Tana-Beles area has been identified as an economic `growth corridor' by the government of Ethiopia and the World Bank. The intention is to stimulate economic growth and reduce poverty through the development of hydropower and a number of irrigation schemes. However, the likely environmental implications of these developments and specifically the impact on lake water-levels have not been fully evaluated. An evaluation is crucial because the lake is important to the livelihoods of many people in a number of different ways including domestic water supply, fisheries, grazing and water for livestock, as well as reeds for boat construction. In addition, the lake is important for water transport and a tourist destination. Flooding in Lake Tana sub-basin of Upper Blue Nile are attributed to rivers that overflow or burst their banks to inundate low lying areas. Ribb and Gumara rivers are the major rivers in Lake Tana sub-basin that flow through the flat fields of Fogera flood plain. The water evaluation and planning was used to simulate planned hydropower and irrigation development. Simulation of water demand and estimated downstream environmental flows was conducted for a 30-year period of varying flow and rainfall. Based on the simulation results, water availability for the different proposed irrigation and hydropower schemes was determined. The likely impact of future water resource development' on water levels of the lake was assessed based on the simulation results The simulation results revealed that, if the full future development occurs, on average, 2,207 GWh/y of power could be generated and 548 Mm3/y of water could be supplied to irrigation schemes. However, the mean annual water level of the lake would be lowered by 0.33m with a consequent decrease of 23 km2 in the average surface area of the lake. Besides having adverse ecological impacts, this would also.have significant implications for shipping and the livelihoods of many local people. iv