AGS, a Joint Venture prime consultant, is tasked to provide SFPUC with assistance with planning and alternatives analysis for the repair and improvement of the pipeline and cistern facilities that make up the San Francisco Auxiliary Water Supply System (AWSS). AGS completed an Existing Performance, Operations and Needs Assessments.
Based on existing reports, AGS was tasked to perform geotechnical and seismic safety evaluation of AWSS facilities in the City of San Francisco. The facilities include pipelining tunnels, cisterns, pump stations, reservoirs and tanks. The scope includes development of seismic design criteria and landslide potential evaluation and development of geotechnical criteria for retrofit of structures.
The objective was to review existing configurations, analyze system hydraulics, and make recommendations on pipelines, control systems, seawater intake tunnels, and cisterns to optimize benefits from repairs and improvements to the AWSS, given the potential for seismic activity in the areas.
AGS assisted in planning for the AWSS pipelines, control system, seawater intake tunnels, and cisterns, as well as planning–level assessment of the effects of proposed AWSS modifications on fire insurance premiums for property owners in San Francisco.
A critical goal of this work was to confirm that the AWSS effectively provided required firefighting capabilities after a major seismic event. AGS prepared a Technical Memorandum [TM] presenting the results of their geotechnical study. The conclusions and recommendations presented in the report were based on the subsurface conditions which were identified by reviewing data presented in approximately 800 borings logs from several different sources. The report presented seismic design criteria and geoseismic hazard potential, consequences and mitigation measures for AWSS facilities throughout the City of San Francisco.
AGS was performing additional geotechnical studies for various elements of the project which were identified in the geotechnical design memorandum. The additional geotechnical studies included field exploration and laboratory testing to develop site-specific geotechnical and seismic stability conclusions and recommendations.