Key milestone for the Perris Valley Pipeline extension in Southern California

The Metropolitan Water District (MWD) of Southern California’s Perris Valley Pipeline Interstate 215 (I-215) Crossing Project, which will expand the delivery of water to the Eastern and Western Municipal Water Districts of Riverside County, recently reached a major milestone. Using a 123-inch (312-cm) microtunnel boring machine, the team broke through from shaft 1 of the tunnel to shaft 2, completing the third and final microtunnel drive of the project.

The Perris Valley Pipeline was constructed over a decade ago, but due to geological conditions and higher than anticipated groundwater inflows, the section that would cross I-215 and connect the two portions of the pipeline could not be completed. Mott MacDonald joined the I-215 Crossing project team in 2023 bringing extensive tunnel and shaft expertise. Our role is to provide supplemental experts to MWD’s Construction Management Unit and support the completion of all tunnel work through construction inspection, tunnel engineering support, and schedule review service. We are proud to have supported J.W. Fowler and MWD to help deliver this critical project, which will enhance water delivery capacity to the region.