Downstream Consequences of Ribb River Damming, Lake Tana Basin, Ethiopia

This study assessed the downstream river system adaptation in response to upstream damming on the Ribb River,Ethiopia,to irrigate 15,000 ha. It analyzed the pre-dam morphodynamic trends, developed three dam operation scenarios, and assessed the applicability of physics-based analytical equations and a 1D numerical model. A HEC-RAS 2D hydrodynamic model was also developed to assess the effect of the dam on the flooding extent of the Fogera Plain. The results contribute to knowledge on the hydro-morphological and environmental impacts of dams on downstream river systems.

Format: Paperback / softback
Length: 140 pages
Publication date: 10 January 2022
Publisher: Taylor & Francis Ltd

This comprehensive study assessed the adaptive response of the downstream river system to upstream damming on the Ribb River in Ethiopia, aimed at irrigating 15,000 hectares. It employed a combination of primary and secondary data, along with the application of remote sensing and mathematical modeling techniques. The pre-dam morphodynamic trends of the Ribb River were analyzed for a period of 59 years, utilizing aerial photographs, satellite images, and newly collected field data. Three distinct dam operation scenarios were developed to examine the long-term hydro-morphological consequences of the dam on the downstream river reaches. Furthermore, the study compared the applicability of physics-based analytical equations (Equilibrium Theory) with a 1D numerical model (SOBEK-RE) to determine the least-morphologically impactful dam operation scenario on the river reaches downstream of the dam. Additionally, a HEC-RAS 2D hydrodynamic model was developed to assess the impact of the dam on the flooding extent of the Fogera Plain. This model was employed to investigate the potential implications of hydrological alteration on the ecology of the floodplain wetlands, as they serve as habitats for numerous important fish and bird species. The findings of this study significantly contribute to our understanding of the hydro-morphological and environmental impacts of dams on downstream river systems. The methodologies developed and the insights gained can be utilized to study future hydro-morphological and ecological changes that may arise as a result of other dam operations or climate change.

ISBN-13: 9781032250311