Critical Connections to Large Diameter Pipelines with Short Work Durations

The San Diego County Water Authority (Authority) Capital Improvement Program (CIP) includes several projects requiring large diameter pipeline connections to the existing aqueduct system. Major portions of the San Diego Aqueduct that supplies water to 2.7 million residents and 23 member agencies in San Diego County, California (County) must be shutdown to complete these connections. Since approximately 95 percent of the County of San Diego's water is imported through the Authority's aqueducts, these connections must be completed in the shortest possible time following detailed construction plans and schedules so that water shortages do not occur. This paper will discuss the planning, design, construction and operational issues related to large diameter pipeline connections for the Authority's Twin Oaks Valley Diversion Structure project. This project included multiple large diameter pipeline connections that were completed in time frames as short as eight days. This project also include new cement mortar lines and cement coated (CMLC) steel pipe designed and constructed to connect to existing aqueduct pipe materials such as prestressed concrete cylinder pipe (PCCP). Partnering between the owner, engineer, construction manager, and contractor assisted in successful connections to the San Diego Aqueduct.