Potential impact and mitigation measures of pump irrigation projects on Lake Tana and its environs, Ethiopia

Abstract

Environmental Impact of pump irrigation projects from Lake Tana (Megech - Seraba, Tana Asrate, Tana Mekonta, Tana Wenjeta, and Tana Zegie) was studied from July 2018 to February 2019. Interactions between project activities and environmental parameters were also done by a matrix, and quantitative and qualitative analysis. As a result, identified positive impacts are new job creation, the opportunity to promote traditional agriculture and income increase, whereas land, fisheries and wetland degradation, pollution, deforestation and wildlife, inefficient water use, the decline in soil fertility, erosion, sedimentation, small aquatic animal death, and cumulative impacts are negative ones. Mitigation measures for these impacts to reduce their effects to the minimum level and recommendations have been proposed so that the execution of the projects becomes a success without harming or with the least negative effect on the environment.

Spawning migration of Labeobarbus species of Lake Tana across the Gilgel Abay River Weir, Ethiopia: The challenges to fish spawning migration and proposed management solutions

“…the river itself upstream of the weir, and four main and more than eleven small tributaries of the river) have collapsed due to the weir barrier, endemic species of Lake Tana are threatened with extinction because it is one of the lake's main tributary rivers. Similar threats were reported by Mequanentet al (2021), Mequanent & Mingist (2019), Dejen et al (2017), Anteneh et al (2012) and de Graaf et al (2004) for these species in the lake and other inflowing rivers. Accordingly, this means that 20% of the world's freshwater fish species are threatened or extinct because of human threats (Mora et al, 2007; Myers, 1995; Sala et al, 2000) attributable mainly to the dam and weir construction (Dynesius & Nilsson, 1994).…”

“…Fishers also use prohibited fishing gears that have been banned by the ANRS (2007) and FDRE ( 2003) fisheries proclamations, which has also become problematic. As reported by Mequanent et al (2014Mequanent et al ( , 2021, Mequanent & Mingist (2019), Dejen et al (2017) andde Graaf et al (2007), significant fishing pressures using monofilament and toxic chemicals and barriers during the spawning period is a common practice. As an example, according to the fishers, the average catch was about 13-20 kg/person/day at Gilgel Abay Weir, where they targeted spawners and the catch was higher than elsewhere in the river.…”

“…To this end, over 6000 fishers rely on fishing in the Lake Tana sub‐basin of Ethiopia, which comprises the northeastern part of the Blue Nile basin in East Africa (Mequanent et al, 2021). The populations of multiple fish species in Lake Tana are severely declining, however, with four species being threatened with extinction (Anteneh et al, 2012; de Graaf et al, 2007; Dejen et al, 2017; Gebremedhin et al, 2018; Mequanent & Mingist, 2019; Mequanent et al, 2021).…”

Impact of irrigation practices on Gilgel Abay, Ribb and Gumara fisheries, Tana Sub-Basin, Ethiopia

“…There are also high-water demanding activities such as domestic, municipal, transportation, and industrial purposes. Cumulative effects on fisheries like the studies of Mequanent and Mingist (2019) and Contant and Wiggins (1993) may result.…”

“…Aside from its negative impact, irrigation also has tremendous advantages such as increases in agricultural production ( Bryan et al, 2013 ; Alessandra and Tisorn, 2018 ) and land values ( Mequanent and Mingist, 2019 ); food security, poverty alleviation, rural employment, and improved diets ( Lipton et al, 2003 ; Hussain and Hanjra, 2004 ). Fish production in the irrigation system is also the other advantage ( Gregory et al, 2018 ; Wilder and Phuong, 2002 ).…”