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SARI Relocation – Mainline (including Metering Station)

Client: Orange County Public Works


Project Value: $40M

Project Description: Built in the mid-1970s, the Santa Ana River Interceptor (SARI) sewer line was originally buried about 20 feet below the Santa Ana riverbed. Over time, the amount of soil covering the SARI line had diminished through erosion, leaving the pipeline virtually exposed in some locations. This condition put nearly four miles of the SARI line in jeopardy of failure during storm events. In addition, the U.S. Army Corps of Engineers raised the level of the upstream dam by 30 feet and increased the discharge capacity into the Santa Ana River, increasing the risk of failure. This project replaced the highest risk section of the SARI wastewater pipeline, ensuring reliability, protecting the environment, enhancing flow characteristics, increasing capacity to 43 MGD, and allowing flow to be measured by a new metering station. Some of the key project elements included installing:

  • 20,630 linear feet of Hobas 54-inch fiberglass reinforced pipe (FRP) via the open cut method with depths ranging from 11 to 30 feet
  • 4,000 linear feet of 101.5-inch OD micro tunnel in four drives
  • 2,900 linear feet of 84-inch ID RCP
  • 1,100 linear feet of 99.5-inch ID steel casing construction of a 655 cubic yard cast-in-place below-ground metering station (invert depth of 26 feet) and associated mechanical systems with aboveground CMU building
  • Electrical and telemetry systems
  • 33 pre-cast T-Lock lined 84-inch diameter manholes at depths of 38 feet
  • Six cast-in-place T-Lock lined or FRP-lined manhole structures at 52 feet deep
  • Concrete inlet and outlet structures
  • 70-foot-deep Secant pile shafts for tunneling under the Santa Ana River
  • 800 linear feet of permanent sheet pile protection wall

The scope of the work included removing and replacing 18,000 tons of grouted rip rap and 350,000 square feet of roadway. This project was the first in the United States to have two curved drives and was also the first to use an innovative hydraulic gasketed joint in North America. It set North American micro tunneling records as the longest curve at 2,187 linear feet and the longest compound, or “S”, curve at 1,567 linear feet. Extensive stormwater pollution protection measures (note the project is located within the Santa Ana River floodplain) were required and wildlife mitigation measures (for numerous endangered species) were put into place. These include planting native vegetation, creating spaces for migratory birds and bicyclists, constructing associated landscaping, and restoring habitat.