Lessons Learned from a 72-Inch Pipeline Reline in San Diego

In early 2008 the California Department of Transportation (Caltrans) was scheduled to commence widening of Interstate 15 over the San Diego County Water Authority's Second Aqueduct crossing as part of the I–15 Managed Lanes Projects. As a result, Pipelines 3, 4, and 4A would be impacted by both the work performed by Caltrans and the resulting load caused by the road widening. To ensure protection of the pipelines was completed without impact to Caltrans' schedule a Design Build Request for Proposals was advertised in the summer of 2007. On November 20, 2007 the San Diego County Water Authority, in partnership with the Design Build team of L. H. Woods & Sons, Inc. and Tetra Tech, commenced the relining of three 72-inch Pre-stressed Concrete Cylinder Pipelines directly beneath Interstate 15 utilizing a combination of 1-inch thick steel liners and high strength grout. Early on it was clear that a list of challenges would present themselves due to the proximity of the project to existing residential structures, work preformed during California gnatcatcher breeding season, and two scheduled aqueduct shutdowns in a relatively short timeframe. Despite these challenges the project was completed ahead of schedule and under budget while providing multiple lessons learned for the project team in the following areas: environmental, public affairs, and communication. In order to expedite the commencement of relining ahead of the proposed Caltrans work, the Water Authority filed a categorical exemption to comply with the California Environmental Quality Act (CEQA). The categorical exemption coupled with the dissemination of many suitable habitats by the wildfires of 2007 magnified a potential problem that a breeding pair of gnatcatchers could have in halting construction of the project until the end of the gnatcatcher breeding season. Prior to construction, the project team had already anticipated some of the challenges associated with the project's close proximity to surrounding residences. One projectsite / access point was located in the middle of a common area in a condominium complex, twenty feet from the nearest residence while another site was in the middle of an owner's "extended" backyard. This proximity resulted in close scrutiny by the surrounding public who paid particular attention to the aesthetics of the site, something that had not been considered on prior projects. Ultimately, many of the complaints and questions received were mitigated with an effective approach to communicating the project information. However, the most critical element to the success of the project was clear, rapid, and efficient lines of communication. Never was it more evident than around the two scheduled aqueduct shutdowns requiring coordination not only among the project team, the contractor, and sub consultants but, including the multiple departments within the Water Authority. The experiences and lessons from this project continue to benefit not only the Water Authority's projects, but the public as a whole.