American River Channel Reconstruction and Intake Facility

This was a joint project between the US Bureau of Reclamation (USBR) and Placer County Water Agency (PCWA). The project includes reconstruction (grading, placement of riprap, and subsurface cutoffs) of approximately 1.5 miles of river channel, design and construction of new intake facilities for PCWA, and closure of the dam diversion tunnel.
Blackburn Consulting evaluated subsurface conditions including alluvial depth/composition and structural geology, and provided options for excavation and fill placement, rock slope stability, design and construction of structures, and construction testing/inspections. We also assisted in preparation of specifications for grading, foundation construction, blasting, and rock bolting. Significant challenges included site access and methods to determine depth of fill/alluvium overlying bedrock (for foundations and cutoffs), and defining the variety of materials within the site and their reuse within the project. We coordinated with the USBR in obtaining borehole and excavator data on bedrock depth and quality and groundwater elevation. Exposed rock structure/extent mapping was completed and extrapolated to covered areas and combined with subsurface data for preliminary evaluation and design recommendations.

Location Auburn, California
Agency/Owner USBR and PCWA
Timeframe 2005 to 2007
Construction Costs $70 million