DIAMOND VALLEY LAKE, OBSERVATIONS DURING INITIAL FILLING

摘要

Diamond Valley Lake is a new 800,000 acre-foot reservoir near Hemet, California. The reservoir is constructed in an open ended east-westerly valley with a low range of hills to the north. There are three dams enclosing the reservoir; a 284-foot tall West Dam and a 184-foot tall East Dam enclosed both ends of the valley and a 129-foot tall Saddle Dam filled a low area of the north rim hills forming the north side of the reservoir. All three dams have earthen cores buttressed on both sides by rockfill shells. The dams were extensively instrumented during construction by embedded piezometers, inclinometers, settlement sensors in the cores and foundations and the crests, upstream and downstream were instrumented by pillar-mounted and surface-mounted survey points and accelerographs. The piezometers have been used to monitor water levels in the cores and foundations and the remaining instruments to monitor any potential vertical and horizontal movements within the cores and at the crests, upstream, and downstream areas. The dams were completed in late 1999 and initial filling was immediately commenced; the reservoir is now fully in operation. Since the completion, the three dams have been inspected numerous times. The instruments have been monitored systematically using Global Positioning System and Automated Data Acquisition System during the initial filling as well as the normal reservoir operation. Instrumentation readings have been used to evaluate as-built deformation/compressibility and hydraulic characteristics of the core and shell materials. Observation of the performance of the three dams and appurtenant structures will be described since the initial filling.