For monitoring the height changes along the High Dam body, eight leveling lines were established at different elevations during its construction. The leveling measurements were carried out monthly by the Geodetic Branch of the High Dam and Aswan Dam Authority (HADA) since 1970 till now.
The present work focuses on the data analysis from leveling along eight lines crossing the High Dam body during the period from 2000 to 2006. The analysis reveals to different tendencies of the High Dam body. Rates of the subsidence at most benchmarks of the leveling lines range between 1-2 mm/yr. Rates of the setting of the High Dam body is trending to be stable. The correlation between these rates and water level changes at the up- and down-stream sides is absent during the observed period.
For monitoring the horizontal and vertical movements in the High Dam area, a local GPS network consisting of 9 geodetic stations and one leveling line joining the High Dam and Aswan Dam, were established in 2000. The measurements were carried out during the period from 2002 to 2006. Seven campaigns of GPS and four leveling measurements were carried out in the study area. The measurements are correlated to the water level changes in the lake, as well as to the seismic activity in the area. The displacements for each epoch of observations were calculated and the deformation analysis was performed. The horizontal and vertical displacements vary between 1 to 2 and 0.1 to 1 mm/yr, respectively. The vertical and horizontal rates and strain accumulations are small, which reflect the stable situation, and demonstrates a new information about the present state of the High Dam body and surrounding areas.