BOARD AGENDA MEMORANDUM
SUBJECT:
Title
Receive an Update on the Condition of the Almaden Valley Pipeline.
End
RECOMMENDATION:
Recommendation
Receive an Update on the Condition of the Almaden Valley Pipeline.
Body
SUMMARY:
The Almaden Valley Pipeline (AVP) consists of approximately 12 miles of 72-inch to 78-inch diameter Prestressed Concrete Cylinder Pipe (PCCP) and Welded Steel Pipe (WSP). The pipeline was constructed in three (3) segments: Unit I (4.4 miles) was constructed in the 1960's, and Unit II Phase I (3.5 miles) and Unit II Phase II (3.7 miles) were constructed in the 1980's. The AVP is used to supply raw water from the Central Valley Project to Santa Clara Valley Water District's (Valley Water) water treatment plants and groundwater recharge facilities.
During the April 27, 2017 Board meeting, the Board authorized the sole source procurement of PCCP Electromagnetic (EM) inspection and Acoustic Fiber Optic (AFO) monitoring condition assessment equipment and services.
When the pipelines are shut down for maintenance and rehabilitation, the EM inspection technology is used internally to scan the structural components of PCCP for broken prestressing wires. The resulting data forms the baseline for PCCP condition assessment. Once the pipelines are returned to service, the AFO system continually monitors, records, reports, and tracks the prestressing wire break events in PCCP pipelines twenty-four (24) hours a day, seven (7) days a week. The EM Inspection and daily AFO prestressing wire break data are used to assess and update the current condition of the PCCP.
During the September 22, 2017 Board meeting, the Board awarded the AVP Inspection and Rehabilitation Project to Con-Quest Contractors, Inc. An EM inspection was conducted in conjunction with the Project. The EM Inspection revealed a substantial number of distressed PCCP pieces sporadically dispersed throughout the 3.7-mile Unit II Phase II portion of AVP.
On December 5, 2017, the Chi...
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