Wetlands of the Lake Tana Watershed

Abstract

The Lake Tana watershed lies within the Afro-tropical wetland system in Ethiopia. The total wetland area of the watershed is estimated to be 32,157 ha. These wetlands have different physical and hydrological, chemical and water quality, and biological and habitat functions. The Lake Tana watershed wetlands and its associated rivers holds about 28 species of fishes, of which fifteen are endemic, and there are over 300 species of birds recorded so far. The watershed is famous for having natural pasture land and is the home of the Fogera cattle. The wetlands in the Lake Tana watershed extend from the headwaters of Guna and Gishe-Abay to Fogera and the Dembia floodplains. The river mouths of the Gelda, Gumara, Arno-Garno, Megech, Dirma, Abagenen, Gilgel Abay and Infranz are the major delta wetland ecosystems. Yiganda and Amluk wetlands are of the lacustrine wetland type formed by the lake water while Chimba and Infranz wetlands are the common riverine wetlands. Several other wetlands are formed from cold and hot springs. There are also man-made wetlands such as the Koga Dam area and other constructed small water bodies and weirs as well. Lake Tana watershed wetlands provide habitat for globally threatened and endangered species. However, wetland loss is evident wherever major developments such as dams, irrigation schemes and conversion projects are present in the developing world. Humans usually and very dramatically accelerate natural processes. In the Lake Tana watershed, human induced threats such as conversion of wetlands into agriculture, draining of wetlands and lack of defined ownership of the resource is the main threats.