Reservoir-Induced Land Deformation: Case Study from the Grand Ethiopian Renaissance Dam

Yu Chen,Natthachet Tangdamrongsub,Mohamed Ahmed,Dorina Murgulet

doi:10.3390/rs13050874

Abstract

The Nile River stretches from south to north throughout the Nile River Basin (NRB) in Northeast Africa. Ethiopia, where the Blue Nile originates, has begun the construction of the Grand Ethiopian Renaissance Dam (GERD), which will be used to generate electricity. However, the impact of the GERD on land deformation caused by significant water relocation has not been rigorously considered in the scientific research. In this study, we develop a novel approach for predicting large-scale land deformation induced by the construction of the GERD reservoir. We also investigate the limitations of using the Gravity Recovery and Climate Experiment Follow On (GRACE-FO) mission to detect GERD-induced land deformation. We simulated three land deformation scenarios related to filling the expected reservoir volume, 70 km3, using 5-, 10-, and 15-year filling scenarios. The results indicated: (i) trends in downward vertical displacement estimated at −17.79 ± 0.02, −8.90 ± 0.09, and −5.94 ± 0.05 mm/year, for the 5-, 10-, and 15-year filling scenarios, respectively; (ii) the western (eastern) parts of the GERD reservoir are estimated to move toward the reservoir’s center by +0.98 ± 0.01 (−0.98 ± 0.01), +0.48 ± 0.00 (−0.48 ± 0.00), and +0.33 ± 0.00 (−0.33 ± 0.00) mm/year, under the 5-, 10- and 15-year filling strategies, respectively; (iii) the northern part of the GERD reservoir is moving southward by +1.28 ± 0.02, +0.64 ± 0.01, and +0.43 ± 0.00 mm/year, while the southern part is moving northward by −3.75 ± 0.04, −1.87 ± 0.02, and −1.25 ± 0.01 mm/year, during the three examined scenarios, respectively; and (iv) the GRACE-FO mission can only detect 15% of the large-scale land deformation produced by the GERD reservoir. Methods and results demonstrated in this study provide insights into possible impacts of reservoir impoundment on land surface deformation, which can be adopted into the GERD project or similar future dam construction plans.

Highlights

Licensee MDPI, Basel, Switzerland.The Nile River stretches from south to north throughout the NileRiver Basin (NRB; area: 3.4 × 106 km2 ) in Northeast Africa
Construction; (ii) uses the readily available remote sensing data (e.g., DEM) to investigate and forecast large-scale land deformation caused by a reservoir impoundment; (iii) uses a modelling/simulation approach as an alternative technique to quantify reservoir-induced land deformation in area with limited field observations (e.g., Global Positioning System (GPS)); and (iv) provides a comprehensive understanding of limitations of using the Gravity Recovery and Climate Experiment (GRACE)-FO mission to detect
This study provided an innovative approach for predicting large-scale land deformation induced by the impoundment of 70 km3 of water within the Grand Ethiopian Renaissance Dam (GERD) reservoir

Summary

Introduction

The Nile River stretches from south to north (length: 6853 km) throughout the Nile. River Basin (NRB; area: 3.4 × 106 km2 ) in Northeast Africa. The Nile’s primary tributaries are the White and Blue Niles (Figure 1a). The White Nile flows from Lake Victoria, and runs through Uganda into Sudan. It meets the Blue Nile (which originates from Lake Tana in Ethiopia; Figure 1b) at the city of Khartoum in Sudan, flows through Egypt into the Mediterranean Sea (Figure 1a).

Results

Discussion

Conclusion