Deformation Monitoring of Reservoir Dams Using GNSS: An Application to South-to-North Water Diversion Project, China

Deformation monitoring plays an important role in performance monitoring to ensure the reservoir dams and embankments are functioning as designed. This work should be the first deformation monitoring application of GNSS in China's huge South-to-North Water Diversion Project. A GNSS deformation monitoring system, equipped with 4G data transmission and automated data processing software, is established at Shuangwangcheng Reservoir, an important regulation control project on the Eastern Route. Precision evaluations of different observation sessions from both GPS and BDS are conducted, and results show that the performance of BDS is comparable to that of GPS, especially for longer observation session solutions. The 1 mm horizontal and 2 mm vertical precisions of daily solutions meet the deformation monitoring requirement of the project. The deformation time series reveal an uneven settlement of Shuangwangcheng Reservoir dam. The causes of deformation are analyzed and the water level change in the reservoir is deemed as the main factor.