Water Security Problems of Lake Tana and Its Possible Management Options: A Review

Abstract

Lake Tana is the largest lake in Ethiopia and accounts for 50% of the country's freshwater resources. It provides a unique habitat for biodiversity and plays an economic role via tourism, electricity, agriculture, fishery, and, most importantly, it provides drinking water to the local inhabitants. Because of its immense water resource potential for socioeconomic development, Lake Tana has been identified as a major economic corridor in the country. Given the importance of the lake to the region and nation’s economy, human health, and livelihoods, assessing the water security problems of the lake in terms of water scarcity and quality is critical for its sustainable management. Doing so, studies on water level fluctuation and water scarcity, and physicochemical and related hydrological and biological features of the lake, which have been reported in the literature over more than a decade, were reviewed, and the studies showed that water level fluctuation was observed and resulted in water scarcity problems for surrounding communities. In addition to water scarcity and water fluctuation problems, the lake's trophic status has also gradually changed from oligotrophic to mesotrophic and eutrophic. In addition, faecal pollution, heavy metal pollution, and toxicogenic cyanobacteria are detected in the lake, especially on the shores and its tributary river mouths. Moreover, Lake Tana is infested by the ecologically dangerous and worst invasive weed, the so-called water hyacinth, with rapid area coverage and has resulted in dominant other important floras and posing a significant negative impact on water quality, biodiversity, fishing, water supply, water transportation, and other economic activities. There are options recommended to manage the lake. In this regard, different lake ecosystem management options like delineation of buffer zones, integrated watershed management, awareness creation about the lake and its associated wetlands, development of waste management practices, eradicating/reducing water hyacinth, and enforcement of environmental related policies and Strategies are recommended for sustainable management of Lake Tana.