Pipeline 3 Desalination Relining—San Marcos to Twin Oaks

Butier Engineering, Inc. provided construction management, contract administration, and inspection services for the Pipeline 3 Desalination Relining San Marcos to Twin Oaks project. SDCWA relined five miles of Pipeline 3 through the unincorporated community of Twin Oaks Valley into the northern part of the City of San Marcos. Pipeline 3 was relined to accommodate pressurized flows from the new Carlsbad 50 MG Seawater Desalination RO Treatment Plant.

The Pipeline 3 Desalination Relining project included upgrading 27,000 feet of existing 72- and 75-inch diameter pipe with new welded steel liners; fabricating and installing 494 feet of 69-inch outside diameter welded steel pipe at seven access portals; fabricating and installing 448 feet of 67 ¾-inch outside diameter welded steel pipe at eight access portals; and replacing 47 feet of 72-inch steel pipe with new 67 ¾-inch outside diameter welded steel pipe.

Additional work included traffic control; dewatering; fabricating, installing and removing interior bulkheads; SWPP; excavating and backfilling; temporary sound walls and fencing; welding; grouting between liners and existing pipe; placing field-applied cement mortar lining; installing cathodic protection monitoring stations; placing reinforcing steel and concrete encasement; structure rehabilitation; installing new pipe outlets and air releases; and asphalt slurry seal of the Vallecitos Water District access road.