Sugar Pine Dam

The US Bureau of Reclamation (USBR) constructed the 205-foot-high zoned, earth-fill Sugar Pine Dam in 1982 to create a 6,920 acre-foot reservoir. Now owned by the Foresthill Public Utilities District (Foresthill PUD), the dam has on-going monitoring and reporting requirements under the jurisdiction of the state Division of Safety of Dams (DSOD).

Since 2005, Blackburn Consulting has assisted Foresthill PUD in meeting the dam’s monitoring and reporting requirements. To begin, Blackburn performed a desk audit of USBR historical explorations, construction drawings and reports, USBR instrumentation data, PUD instrumentation data, and DSOD files. We met with Foresthill PUD and DSOD personnel to review instrumentation, embankment conditions, appurtenant structures, and general site conditions. We then prepared data summaries and recommendations based on our findings. Recommendations included elimination of some instruments from future monitoring, and continued monitoring of other instruments for future performance evaluation. Instruments included:

• embankment measuring points,
• concrete structure deformation measurement points,
• crest and borehole extensometers,
• inclinometers,
• rock slope deformation measurements,
• twin-tube, pneumatic and porous-tube piezometers,
• weir seepage monitoring,
• and earth pressure monitoring.

Blackburn has prepared yearly monitoring reports for the dam since 2005.