Investigations of the filling procedure of the Grand Ethiopian Renaissance Dam and its potential impact for the downstream countries using multi-satellite optical and radar imagery

Abstract:

Global climate change is expected to impact many regions of the world in drastic and different ways. Some regions are projected to experience more and more intense droughts and potential water shortages, which makes proper water management policies critical in the future of many countries. The Grand Ethiopian Renaissance Dam (GERD), formerly known as the Millennium Dam, is reported under filling at an unnatural rate. The project opens to conflicts and regional political issues for filling of the dam reservoir despite no deal being reached during the talks and the uncertain impact of this GERD for the downstream water bodies. In this study, the analysis of the multi-source satellite imagery shows the procedure of this project. The generated time-series using Sentinel-1 SAR imagery is displaying the number of classified water pixels in the dam from early June, 2017 to July, indicating a contrasting trend in July 2020 for the upstream/downstream water bodies: upstream of the dam rises steeply while downstream decreases. Our time series analysis also shows the average daily precipitation rate in the Blue Nile basin in Ethiopia having no abnormal precipitation in the 2020. Simultaneously, the study also demonstrates the drying up trend in the downstream Lake Nasser in the southern Egypt. The study suggests that attention should be drawn to the connection between the GERD filling and possible severe drought in the downstream countries.