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IWMI RESEARCH REPOR T Related Publications Awulachew, S. B.; McCartney, M.; Steenhuis, T. S.; Ahmed, A. A. 2008. A review of hydrology, Evaluation of Current and sediment and water resource use in the Blue Nile Basin. Colombo, Sri Lanka: International Water Management Institute (IWMI). 81p. (IWMI Working Paper 131). Future Water Resources www.iwmi.org/Publications/Working_Papers/working/WOR131.pdf 134 Awulachew, S. B.; Yilma, A. D.; Loulseged, M.; Loiskandl, W.; Ayana, M.; Alamirew, T. 2007. Water Development in the Lake resources and irrigation development in Ethiopia. Colombo, Sri Lanka: International Water Management Institute (IWMI). 66p. (IWMI Working Paper 123). www.iwmi.org/Publications/Working_Papers/working/WP123.pdf Tana Basin, Ethiopia Kim, U.; Kaluarachchi, J. J.; Smakhtin, V. U. 2008. Climate change impacts on hydrology and water resources of the Upper Blue Nile River Basin, Ethiopia. Colombo, Sri Lanka: International Water Management Institute (IWMI). 21p. (IWMI Research Report 126). www.iwmi.org/Publications/IWMI_Research_Reports/PDF/PUB126/RR126.pdf Matthew McCartney, Tadesse Alemayehu, Abeyu Shiferaw and McCartney, M. P.; Arranz, R. 2007. Evaluation of historic, current and future water demand in Seleshi Bekele Awulachew the Olifants River Catchment, South Africa. Colombo, Sri Lanka: International Water Management Institute. 48p. (IWMI Research Report 118). www.iwmi.org/Publications/IWMI_Research_Reports/PDF/PUB118/RR118.pdf Postal Address P O Box 2075 Colombo Sri Lanka Location 127, Sunil Mawatha Pelawatta Battaramulla Sri Lanka Telephone +94-11-2880000 IWMI Celebrating Fax +94-11-2786854 E-mail years [email protected] 1985-2010 Website www.iwmi.org International I n t erna tiona l Water Management ISSN: 1026-0862 Water Management Institu t e ISBN: 978-92-9090-721-3 Institute Research Reports The publications in this series cover a wide range of subjects—from computer modeling to experience with water user associations—and vary in content from directly applicable research to more basic studies, on which applied work ultimately depends. Some research reports are narrowly focused, analytical and detailed empirical studies; others are wide-ranging and synthetic overviews of generic problems. Although most of the reports are published by IWMI staff and their collaborators, we welcome contributions from others. Each report is reviewed internally by IWMI staff, and by external reviewers. The reports are published and distributed both in hard copy and electronically (www.iwmi.org) and where possible all data and analyses will be available as separate downloadable files. Reports may be copied freely and cited with due acknowledgment. About IWMI IWMI’s mission is to improve the management of land and water resources for food, livelihoods and the environment. In serving this mission, IWMI concentrates on the integration of policies, technologies and management systems to achieve workable solutions to real problems—practical, relevant results in the field of irrigation and water and land resources. IWMI Research Report 134 Evaluation of Current and Future Water Resources Development in the Lake Tana Basin, Ethiopia Matthew McCartney, Tadesse Alemayehu, Abeyu Shiferaw and Seleshi Bekele Awulachew International Water Management Institute P O Box 2075, Colombo, Sri Lanka i The authors: Matthew McCartney is a senior researcher specializing in hydrology and water resource management at the subregional office for East Africa and the Nile Basin of the International Water Management Institute (IWMI) in Addis Ababa, Ethiopia (email: [email protected]); Tadesse Alemayehu was an independent consultant in Addis Ababa when this report was prepared and is now a lecturer at the University of Bahir Dar, Ethiopia. Abeyu Shiferaw was an independent consultant in Addis Ababa, Ethiopia when this report was prepared and is now the coordinator of an international Nuffic project on integrated river basin management at Addis Ababa University; and Seleshi Bekele Awulachew is a senior researcher and the regional representative for the East Africa and Nile Basin office of the International Water Management Institute in Addis Ababa, Ethiopia. McCartney, M.; Alemayehu, T.; Shiferaw, A.; Awulachew, S. B. 2010. Evaluation of current and future water resources development in the Lake Tana Basin, Ethiopia. Colombo, Sri Lanka: International Water Management Institute. 39p. (IWMI Research Report 134). doi:10.3910/2010. 204 / water resources development / lakes / dams / environmental flows / hydrology / stakeholders / models / irrigation / hydropower / Ethiopia / ISSN 1026-0862 ISBN 978-92-9090-721-3 Copyright © 2010, by IWMI. All rights reserved. IWMI encourages the use of its material provided that the organization is acknowledged and kept informed in all such instances. Cover photograph shows the shoreline of Lake Tana, Ethiopia (photo credit: Matthew McCartney) Please send inquiries and comments to: [email protected] A free copy of this publication can be downloaded at www.iwmi.org/Publications/IWMI_Research_Reports/index.aspx ii Acknowledgements The authors would like to thank Ayalew Gebre and Derese Getachew of Addis Ababa University for their assistance in conducting the stakeholder review. They are grateful to the Ethiopian Electric Power Corporation, the Federal Ministry of Water Resources, the National Meteorological Agency and the Central Statistical Agency of Ethiopia for the provision of data. Project This report presents findings from project number 36 entitled “Improved Planning of Large Dam Operation: Using Decision Support Systems to Optimize Livelihood Benefits, Safeguard Health and Protect the Environment” of the CGIAR Challenge Program on Water and Food (CPWF). The following organizations collaborated in the research conducted for this report. International Water Management Institute, Addis Ababa, Ethiopia Addis-Ababa University, Addis Ababa, Ethiopia Southern Waters, Cape Town, South Africa Water scarcity is one of the most pressing issues facing humanity today. The Challenge Program on Water and Food (CPWF), an initiative of the Consultative Group on International Agricultural Research (CGIAR), contributes to efforts of the international community to ensure global diversions of water to agriculture are maintained at the level of the year 2000. It is a multiinstitutional research initiative that aims to increase water productivity for agriculture-that is, to change the way water is managed and used to meet international food security and poverty eradication goals-and to leave more water for other users and the environment. The CPWF deals with complex agriculture-related systems, for which there are a growing number of stakeholders generating information. Its community-of-practice works in innovative ways to collate, unify, organize, extract, distill and share the ideas, information and knowledge to allow next-users to gain insights and deduce principles, concepts and cause-and-effect relationships from its research results. To help achieve this, the CPWF focuses on building multi-disciplinary north-south and south-south partnerships. www.waterandfood.org iii iv iv Contents Acronyms and Abbreviations vi Summary vii Introduction 1 The Study Area 2 Impacts of the Chara Chara Weir on Lake Tana Outflow and Environmental Flow Assessment 6 Stakeholder Analysis of the Chara Chara Weir 15 Simulation of Future Water Resources Development 19 Discussion 26 Concluding Remarks 28 References 29 v v Acronyms and Abbreviations ARBWR Amhara Region - Bureau of Water Resources BCEOM Egis Bceom International BS Baseline Scenario DRM Desktop Reserve Model EEPCO Ethiopian Electric Power Corporation EELPA Ethiopian Electricity Light and Power Authority EIA Environmental Impact Assessment EPLAUA Environmental Protection, Land Administration and Use Authority EU European Union FDS Full Development Scenario LDS Likely Development Scenario LTBRC Lake Tana Basin Research Centre ODS Ongoing Development Scenario PaDPA Amhara Parks Development and Protection Authority TBF Tana Beles Flow VEF Variable Environmental Flow WEAP Water Evaluation And Planning (Model) vi Summary Lake Tana is valuable for many people, including adversely affected others. Future development will the communities who live around the lakeshore, exacerbate pressure on the lake. If all the planned those living on islands and close to the Blue Nile development occurs, the mean water level of the River, which flows from it. The area has been lake will drop by 0.44 meters (m), and the average identified as a region for irrigation and hydropower surface area will decrease by 30 square development, which are vital for food security and kilometers (km2) (i.e., 1%) and up to 81 km2 (i.e., economic growth in Ethiopia. This report presents 2.6%) during some dry seasons. There will be findings from an integrated multidisciplinary study prolonged periods of several years during which that was conducted to investigate the implications water levels will be much lower than they would of this development. The study comprised three be naturally. If environmental flow requirements components: i) an environmental flow evaluation; ii) (estimated to average 862 Mm3y-1) are maintained a stakeholder analysis of the impact of current in the reach containing the Tis Issat Waterfall, the infrastructure and water management; and iii) mean water level of the lake will reduce by a further computer modeling of future water resources 0.37 m and the average lake area will reduce by development. The study found that existing