Monitoring of local deformations and reservoir water level for a gravity type dam based on GPS observations

In order to find a possible relation between the reservoir level and the deformation of the Sanalona dam, the horizontal and vertical displacements for a period of 3.5 years using GPS observations were calculated. The GAMIT/GLOBK scientific software was used for the relative processing of GPS observations and annual speeds over the dam of -6.77 mm/yr, -9.95 mm/yr and -1.62 mm/yr were calculated for the N, E and U components, respectively. In addition, the GNSS reflectometry inversion technique was applied to determine the daily reservoir level of the dam, the values obtained were compared with the real reference values of graduated rulers in situ. The GNSS-R achieved a correlation coefficient (q) of 0.97 with a root-mean-square error (RMSE) of 1.36 m and a regression slope of 0.932 m/m. The deformation in the xDam component obtained a greater relation with the reservoir level due to the thrust force generated on the crest. The results demonstrate that it is possible to use a GPS antenna to carry out two monitoring processes together on a dam: (1) determination of displacements and (2) calculation of reservoir level. (c) 2021 COSPAR. Published by Elsevier B.V. All rights reserved.