San Diego First Aqueduct SIPP and Sliplining

Michels Trenchless provided our customer with an alternate solution for the rehabilitation of three 72-inch, horseshoe-shaped tunnels by using past experience with a successful application of sprayed-in-place geopolymer liner on two tunnels and the installation of a 63-inch fiberglass reinforced polymer pipe and grout via sliplining.

The customer had identified groundwater infiltration into its treated water aqueduct during a previous maintenance shutdown that impacted the quality of the water supplied to 4 million people in the service area. With no feasible alternate means of providing treated water to customers, shutdown of the aqueduct for repairs was only possible in the cooler winter months and was limited to 10-day (240-hour) periods based on downstream reservoir capacity and minimum fire reserve quantities. The restrictions led to a schedule which required full rehabilitation of all three tunnels within the span of three allowable shutdowns in a single winter season.

Alternate Delivery methods were critical for the successful completion of the project.