The Moonlight Beach Triple Barrel 72" CMP Pipe Arch Culvert Rehabilitation project is likely the largest single-location UV CIPP installation ever undertaken, restoring three severely degraded 285-foot 72” diameter stormwater culverts with approximately 90,000 lbs of liner by weight over the course of three days in December 2023. A review of this project emphasizes a number of industry best practices pertaining to project preparation and managing rehabilitation environments in both protected coastal ecosystems and open access public spaces. The project took place at Moonlight State Beach in Encinitas, California on a run of three pipe arch culverts conveying stormwater from the primary evacuation channel in the City of Encinitas underneath a beachfront thoroughfare into the ocean. The beachfront area included parking, public beachfront access, and beach volleyball courts. Engineers had to account for saltwater corrosion, severe degradation and voids in the host pipe, and moderate pipe bends in the liner design, as well as maximizing flow capacity in the rehabilitated pipe to minimize the risk of mudslides in the drought-prone area during critical storm events. Project managers had to contend with a finite window of opportunity during which work could take place with risk of ocean tides disrupting the project footprint during high tide. Additionally, the unique location, coastal ecosystem protections, and proximity to public access recreation area mandated a remarkably small jobsite footprint in proportion to the scale of the rehabilitation works.
After this session, attendees will be able to:
1. Explain how to measure and document diameter changes and wear patterns in a coastal stormwater pipe.
2. Implement lessons learned to better project plan for open access public space rehabilitation.
3. Identify ecologically sensible pipe rehabilitation strategies in drought areas or project locations where post rehabilitation cure-water collection and treatment is impractical.
4. Examine unique rehabilitation challenges from this project setting and the benefits and risks of utilizing different equipment and rehabilitation techniques.
Ideal Audience: Water utilities managers and civil engineers tasked with maintaining or rehabilitating large diameter gravity pipes.
Level: Intermediate