The Hetch Hetchy reservoir system is comprised of three earth embankment and three concrete dams that were constructed between 1910 and 1960. This reservoir system is maintained and operated by Hetch Hetchy Water and Power (HHWP), a division of the San Francisco Public Utilities Commission, and provides potable water and hydroelectric power to the city of San Francisco. TERRA Engineers, Inc. was subcontracted by a AECOM/WRE joint venture, to develop a comprehensive Dam Safety Program for all six dams within the HHWP system: O’Shaughnessy, Lake Eleanor, Cherry, Moccasin, Priest and Early Intake.
TERRA was responsible for developing the overall Dam Safety Program Report (DSPR) for the six dams generally following the guidelines of Federal Energy Regulatory Commission (FERC). The DSPR establishes:
• The policies, objectives, and expectations of the HHWP management as they relate to dam safety.
• Responsibility of personnel within the HHWP organization involved in dam safety.
• Required qualifications of personnel involved in dam safety.
• Dam safety related training required of the personnel involved in dam safety.
• Protocols and requirements for communicating dam-safety related matters
• Requirements for record keeping and control of dam safety related documents.
• Need for continuous improvement and period assessments of performance quality of the DSP.
As part of the report, TERRA developed a detailed Surveillance and Monitoring Plan (SMP) specially tailored to each individual dam that specifies how HHWP will monitor and evaluate the on-going performance of that dam in accordance with the overall Dam Safety Program. This effort required an in-depth review of all existing records and instrumentation data for each dam.