The Alameda Dam experienced foundation deformations during construction, which continued at a reducing rate after construction was completed in 1995. The ongoing foundation deformation rates showed an increase in response during a reservoir surcharge event which occurred during the June 2011 flood. This raised concerns regarding the dam’s stability and the client commissioned a comprehensive 2D and 3D stability assessment, as well as an evaluation of the potential impact of the ongoing foundation movements on the appurtenant structures. The structures associated with the dam include a gated chute spillway with a hydraulic jump stilling basin, and low level outlet with a horseshoe-shaped conduit.
The project is being carried out in five phases. Phase 1 involved an assessment of the dam’s stability to assist in developing near-term reservoir operating criteria for 2012. Phases 2 to 5 involve site investigations, assessments of the foundation deformations and the development of remedial measures that may be required to maintain the long term safe operation of the dam and its appurtenant structures, and evaluating spillway upgrades including incorporation of an auxiliary spillway.
- Site inspection
- Instrument data review
- Geotechnical field investigation program
- Structures field investigation program
- Instrumentation and monitoring program
- Deformation and stability analysis
- Assessment of remedial options for the dam
- Structure rehabilitation options
- Spillway capacity upgrade options
- Project management