AN AUTOMATED AND INTEGRATED MONITORING PROGRAM FOR DIAMOND VALLEY LAKE IN CALIFORNIA

The Metropolitan Water District of Southern California has constructed a new reservoir, Diamond Valley Lake, near Hemet, California. This project includes three large earth/rock dams of 2.9 km, 3.2 km and 0.8 km lengths, up to 85 m high, enclosing a valley approximately 7.2 km long and 3.2 km wide. When filling is complete, the reservoir will hold over 986 million cubic metres of water. A plan was developed to monitor the effects of reservoir and dam loads on the dams and their foundations to ensure that any adverse conditions that develop during operation, and especially during initial filling, are detected as soon as possible. Since Diamond Valley Lake is located in a seismically active area, the dam deformation monitoring (DDM) program is supplemented by an on-site GPS area monitoring network that is connected to the continuously operating (GPS) reference stations (CORS) of Southern California crustal motion monitoring system.