Alteration of the Fogera Plain flood regime due to Ribb Dam construction, Upper Blue Nile Basin, Ethiopia

Abstract

The Fogera Plain, Ethiopia, is affected by recurrent flooding of the Ribb and Gumara Rivers. A large dam on the Ribb River is under construction for irrigation, but also to reduce flooding. We investigated the effects of the dam on the flood regime of the floodplain wetlands using a combination of hydrodynamic and a rainfall-runoff models. The model was calibrated based on inundation maps retrieved from Landsat images. Pre-and post-dam model comparison for 10 years shows that the dam will reduce the flooding extent by 11%, as it only regulates 23.8% of the upstream watershed. The flood extent and duration necessary to maintain ecologically significant water depths ( ≥ 0.5 m) show no notable changes. The developed hydrologic and hydrodynamic models can be used to analyze other dam operation and climate change scenarios even though there are uncertainties related to terrain resolution and analysis of hydrological data.

Land Use and Land Cover Change Detection Using the Random Forest Approach: The Case of The Upper Blue Nile River Basin, Ethiopia

“…A 73-meter-high dam and a diversion weir 30 km downstream to irrigate 15 000 ha of land make up the Ribb River Dam. [95] As a result, from the LULC analysis of three historical periods, it can be concluded that all periods indicated a decline in grazing, shrub lands, and forest area and an increase in cultivated land. This study's investigation of LULC change during 40 years between 1983 and 2022 revealed an increase in cultivated land of 47 541 km 2 .…”

“…A 73‐meter‐high dam and a diversion weir 30 km downstream to irrigate 15 000 ha of land make up the Ribb River Dam. [ 95 ]…”