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The Ribb River is one of the components of the  Blue Nile River system located in the North  Western part of Ethiopia. It drains to Lake  Tana, the source of the Blue Nile River. The  Ribb has a length of 130 km, with a catchment  area of 1,812 km2. The average yearly rainfall  of the catchment is 1300 mm, with 80 %  occurring between the months of June and  September. The average and daily maximum  discharge of the river are 15 m3/s and 220  m3/s, respectively. A large dam and a diversion  weir 30 km downstream of the dam are under  construction to irrigate 15,000 ha of Fogera  flood plain (WWDSE and TAHAL, 2007).  Downstream of the dam location, the Ribb is a  meandering river with slope ranging from  0.18% to 0.03%. The river bed material is  dominated by sand with a gravel component in  its upper reaches. Intensive agriculture without  any natural resources conservation,  deforestation, dike construction, pump  irrigation and sand mining are the most  impactful activities in the Ribb watershed  (Tarekegn et al., 2010; Garede and Minale,  2014). The Lake Tana level is regulated since  1995 for hydropower production, which  enhances flooding along the lower river reach.  During the 2006 event, 45 people died, 30,000  persons were displaced and 5371 ha of  agricultural land were inundated (ENTRO,  2010). To prevent flooding, dikes have been  constructed in the lower reach of the river.  This study aims to describe current river  morphodynamic trends, including planimetric  changes for the definition of the pre-dam  conditions of the river. The first part of the work  is presented here with some preliminary  results, focusing on the river planimetric  changes. This paper describes the initial state  of the study. 

Original languageEnglish
Pages90-91
Publication statusPublished - 2017
EventNCR-Days 2017 - Wageningen, Netherlands
Duration: 1 Feb 20173 Feb 2017

Conference

ConferenceNCR-Days 2017
CountryNetherlands
CityWageningen
Period1/02/173/02/17
OtherNetherlands Centre for River Studies is a corporation of the Universities of Delft, Utrecht, Nijmegen, Twente and Wageningen, UNESCO-IHE, RWS-WVL and Deltares

ID: 42134362