Deformation Monitoring at Diamond Valley Lake
Diamond Valley Lake is the largest water reservoir in southern California.
In order to monitor the stability of its three earthen dams, the Metropolitan Water District (MWD) of Southern California has constructed a seven station continuous GPS network.
Leica GPS reference stations, sampling at 2 seconds, stream their data by radio modem to a central computer system.
The data are collected and analysed in real-time. The software performs a full network analysis, and provides real-time and time-averaged position solutions. Also, the software incorporates motion alarms, and remote status displays.
View a horizontal and vertical scatter Screen Shot of four monitoring stations being positioned relative to the reference station WDR. Three tests were performed demonstrating Geodetics technology:
Displacement Test – An antenna motion test. The antenna at WDN was manually moved.
RTD illustrates the change in the N, E and U coordinates of the vector from the reference station (WDR) to WDN. The right frame shows the map view (N versus E).
Positioning Test – A typical ‘operational’ view of the antenna motion test. This screenshot was taken well after the antenna was moved. The top line of plots shows apparent motion (at 2 second intervals) during the last five minute analysis cycle. The minor apparent motion is actually multipath noise. The lower line of plots show successive 5-minute averages from the last several hours. Note the step. And that an alarm was triggered.
Acknowledgement: Raw data and photo courtesy of Metropolitan Water District of Southern California