Ethiopia is blessed with ample water resources. Hence, despite abundance in some parts the country is highly water-scarce due to lack of water control infrastructure. This book provides results of a broad assessment of water resources based on performance and impact aspects of climate change. There are 12 major river basins in Ethiopia seven of which flow across the international border to Sudan, Somalia or Kenya. Some 74 percent of the estimated annual flow of 110 billion cubic meters flow out of Ethiopia. Irrigation and hydro-electricity generation are the main economic uses to which the water is put. Some 161,010 hectares are currently irrigated out of a potential area of 3.5 million hectares, and some 1,698 GWH generated per annum out of potential power generating potential of 135, 311 GWH per annum.