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Air vacuum air release valves (AVAR) are float operated valves which are common to water delivery systems.  The AVAR’s function is to allow volumes of air to be exhausted from or admitted into the pipeline to protect the system from a loss of capacity and prevent the pipe from collapsing in the event of a break in the pipe.  There are twenty-six AVARs on the Lower Reach of the SCC.  Of these, twenty have been rehabilitated; the remaining six will be completed by an outside contractor over the next two fiscal years. Replacement of the AVARs is a USBR Category 1 recommendation.

The riser pipe is the functional connection between the SCC and air vacuum air release valves (AVARs) located in the system.  The riser pipe sits directly on top of a man-hole cover and supports a gate valve that sits below the AVAR. Riser pipes exist at all 57 AVAR locations. Twenty riser sections have been identified to pose an operational risk.  Replacement and/or relocation of the riser pipes affiliated with the air vacuum air release valves will ensure the functionality of this system component.

Blow-off structures exist on all low points of a water distribution system. The components included in these structures include man-hole covers, lower riser sections, an upper spool section, a gate valve, and blow-off piping. There are a total of sixty-five blow-off structures in South Coast Conduit system.  The project consists of replacing the man hole covers, lower risers, gate valves, upper spools, and discharge piping within the Upper and Lower Reaches of the SCC.  The project would be completed in conjunction with the AVAR valve replacement and relocation project and coordinated with the affected Member Units during the required system shutdown.