DVWS 12-inch water main replacement - Phase 1
The City of Pleasant Hill (City) operates a non-potable water system, the Diablo Vista Water System (DVWS), which supplies irrigation raw water to approximately 475 homes within the City. Water is supplied to the DVWS by a pump station which draws untreated water from a canal (operated by the Contra Costa Water District (CCWD)). This section of water main is the distribution line from the pump house to the system. It is over 65 years old and has experienced 12 leaks due to pipe failure in the past which requires the entire system to be shut down. Replacement of the water main is needed in order to continue to provide reliable service to the system.
Phase I: prepared plans and specifications for the removal and replacement of approximately 1,275 linear feet of 12” water main on Stevenson Drive, Byron Drive, and Marvin Drive including all valves, laterals, and necessary appurtenances, along the existing right-of-way (roadway) and expedite work for completion by April of 2018 (when the irrigation system is offline). The project will improve the long-term reliability of the water system by replacing existing cast iron pipes and fittings with PVC pipe and ductile iron valves and fittings in combination with cathodic protection (protect metal parts from corrosive soils).
Phase II: will provide for design level plans and specifications to remove and replace the remaining section of 12” water main located within the Contra Costa Canal (United States Bureau of Reclamation (USBR)) right-of-way, and between Oakvue Road and Roberta Avenue. This will require a lengthier process to obtain permits from USBR and new easements with private property owners once the best feasible alignment is determined. Preliminary engineering work in this section has been completed. Final engineering plans are scheduled for completion next year. Phase II would be funded at a later time as funds became available.
Construction Update - Week of April 9th
Through April 6th, the City’s contractor, Stoloski and Gonzalez, Inc., has completed 1,275 feet of 12” water main replacement on Marvin Drive, Byron Drive, and Stevenson Drive. This work completes 100% of the amount of pipe included in the bid schedule, yet there remains a section of pipe to be installed on Stevenson Drive in order to reach the U.S. Bureau of Reclamation property line. The design engineer confirmed that they made an error in the quantity of pipe to be included in the bid schedule. The City will issue a change order to install 100-ft of additional 12” water main which will account for the majority of the 5% contingency. The remaining 160-ft of 12” water main on Stevenson Drive will be added to the Phase 2 project.
This week the contractor will install 100-ft of 12” water main on Stevenson Drive per change order (Tuesday 4/10), perform the pressure test (Wednesday 4/11), excavate to connect the new pipe to the existing pipe (Wednesday 4/11 – Thursday 4/12), and install six service lines to new concrete boxes (Thursday 4/12 – Friday 4/13). Assuming nothing goes wrong, water will be available to the system by the end of Thursday 4/12.
CCWD performed maintenance on the canal last week. Canal water is not yet available.
Construction Update - Week of April 2nd
Through the end of March, the City’s contractor, Stoloski & Gonzalez, Inc., has replaced 690 feet of 12” water main (54%) on Marvin Drive and Byron Drive and installation of 6 of 6 saddles/corp stops. He will continue replacing pipe on Stevenson Drive through the first week in April and expects to be substantially complete by April 11th.