Bahir-Dar Fisheries and Other Aquatic Life Research Center, P O. Box 794, Bahir-Dar, Ethiopia
Received: 25 September, 2014; Accepted: 10 December, 2014; Published: 12 December, 2014
Dereje Tewabe, Bahir-Dar Fisheries and Other Aquatic Life Research Center, P O. Box 794, Bahir-Dar, Ethiopia, Email:
Tewabe D (2015) Impacts of Furrow Irrigation on Shesher and Welala Natural Reservoirs of Lake Tana Sub Basin, Ethiopia. Int J Aquac Fishery Sci 1(1): 001-005. DOI: 10.17352/2455-8400.000001
© 2015 Tewabe D. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Eco-tourism; Eragrastis teff; Fisheries; Floodplain and intervention
The survey was conducted from March 2012 to March 2013 based on field observations and samples. Shesher is natural reservoir of Lake Tana found at coordinates of 0350300 and 1322162 UTM and at altitudes 1805 a.s.l. Welala natural reservoir is found at UTM coordinates of 0348348 and 1326081 with altitude of 1804 a.s.l. The area of Shesher and Welala was estimated about 500 ha and 110 ha respectively, which are impounded by open water for extended period of a year and both with maximum depth of 3 m during rainy season. Both reservoirs filled their capacity during the rainy season through the inflow river of Ribb and the surrounding flood plain. But during pick dry season of March, 2012 and March 2013 the survey showed unexpected, amazing and sudden death of a home for many biodiversity that both Shesher and Welala natural reservoirs dried up totally. Birds fetch their food from remnants small shrink wet mud spot and it is not uncommon to see remnant dead fishes eaten by birds. This is due to several and unlimited human encroachments mainly for crop cultivation, with out any rules and regulations. Major crops cultivated by drained two reservoirs using gravitational force were Eragrastis teff, Cheak pea, Grass pea, Lentils and Safflower. During dry season no one could be able found drinking water even for their animals and humans, inhabitants started digging well to fetch water from the middle of Shesher and Welala reservoirs. The drainage system was carried out at every 50 m intervals by making large furrows in both sides of two reservoirs until their water totally vanished. These reservoirs should be properly and sustainably exploited by designing appropriate interventions with out land use change, for instance it could be serve for fisheries, ecotourism and livestock sectors.
Direct effects of climate change on wetlands are likely to be accentuating by human induced changes that will increase stress on wetland ecosystems. Up to 60% wetlands have been destroyed in the last 100 years due to drainage, conversion, infrastructure development and pollution. These changes could have been responsible for most of the loss in freshwater biological diversity in the United States in recent decades . Water demand is projected to increase steadily during the coming decades. However, climate change is expected to lead to a decrease in water availability, especially in arid and semi-arid areas. To address this problem, many countries will need to continue efforts to increase reservoir storage capacity to meet the increasing demands for freshwater.
Given the fragility of wetlands, its importance for water supply and the growing pressures to convert them to agriculture uses, there is an urgent need for sustainable use of wetlands. This requires management regimes, which help to maintain some of the natural characteristics of wetlands while also allowing partial conversion to allow activities, which can meet the economic needs of communities. A balance has to be made between the environmental functioning of the two wetlands and their use for livelihood purposes. The purpose of this survey is therefore, to evaluate the current encroachment status of Shesher and Welala natural reservoirs in Lake Tana sub basins.
To evaluate the current status of Shesher and Welala natural reservoirs with respect to anthropogenic activities and able to propose possible solutions
Materials and Methods
The study was conducted in the north eastern part of Lake Tana (source of the Blue Nile). The lake is the largest one (3150 km2) in Ethiopia, comprising 50 % of the total freshwater resources of the country. It is a shallow lake with a mean depth of 8 m and maximum depth of 14 m, situated 1800 m above sea level. Seven large, permanent rivers and about 40 small seasonal rivers feed the lake. The trophic status of Lake Tana is oligotrophic to mesotrophic [2,3]. Shesher and Welala natural reservoirs are found just at the boundary of the lake in fogera floodplains of Fogera woreda of South Gondar zone (Figure 1). These are breeding sites mainly for Clarias gariepinus fish species but not endemic Labeobarbus species of Lake Tana . Fishing activities during the breeding seasons (rainy seasons) and post rainy seasons are immense than ever, fishermen used spears and seining as fishing gear during these seasons respectively.