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W. A. Rasic Construction Continues Their Work on the North City Pure Water Pipeline, Dechlorination Facility and Subaqueous Pipeline Project
By Brian Hoover, Senior Editor / Photos provided by: Brian Hoover, CMS, LLC and W.A. Rasic Construction
The Pure Water Program
Pure Water San Diego represents the City of San Diego’s strategic initiative spanning several years, aimed at sourcing almost half of the city’s water locally by 2035. By employing established water purification techniques, the Pure Water San Diego Program transforms recycled water into potable, high-grade drinking water, ensuring safety and quality. This initiative presents a financially prudent solution for San Diego’s water requirements, fostering a dependable and environmentally sustainable water source for generations to come in San Diego.
Phase 1 of the Pure Water Program is a significant initiative aimed at reducing the City’s reliance on imported water by producing 30 million gallons per day of high-quality purified water through 12 different projects. These projects are essential for securing a local, drought-resilient water supply for San Diegans. The Pure Water Program involves the construction of major water infrastructure, including pipelines, pump stations, and treatment facilities, across various communities such as Morena, Bay Park, Bay Ho, Clairemont, University City, Miramar, and Scripps Ranch.
One of the 12 projects within Phase 1 of the Pure Water Program is the North City Pure
Water Pipeline, Dechlorination Facility, and Subaqueous Pipeline. This $123,456,000 contract was awarded to W.A. Rasic Construction, who received notice to proceed on June 1, 2023, with an estimated completion in early 2025. The W.A. Rasic Construction team is installing around 8-miles of 48-inch welded steel pipeline and associated components. This includes six trenchless tunnel crossings and the construction of a new dechlorination facility made of cement mortar masonry. The facility features two 4,000-gallon chemical tanks, feed pumps, analyzers, forced air ventilation systems, fill and dosing piping, valves, and related infrastructure.
W.A. Rasic Construction Takes On Numerous Challenges
Ryan Plunk is the Senior Manager for W.A. Rasic (W.A. Rasic) the North City Pure Pipeline Project. “This very and up Scripps Ranch all the way to the Miramar Reservoir,” says Plunk. “In addition to the open-cut pipe sections, there are four jack and bore operations performed by subcontractor, Golden State Boring. The locations of the four jack and bores are at the BNSF railroad crossing on Miramar Road, underneath an existing storm drain on Via Pasar, beneath a large diameter water line on Eastgate Mall, and under the I-15 freeway.”
According to W.A. Rasic Project Manager, Moses Vallejo, most of the excavating work is done at night. “The local communities have established agreements with the City of San Diego to keep the excavating and other heavy civil work on night schedules. We set traffic detours, remove the traffic plates, and begin excavating planned sections every night. Once the nightly section is complete, we replace the road plates and do it all again the next night,” says Vallejo.
“Miramar Road is heavily traveled by commuters and located very close to the Top Gun Miramar Marine Corps Air Station. There are a lot of moving pieces, and it is a critical point of emphasis to minimize construction and noise related impacts with the local residents, businesses, and military base, while also attempting to be as efficient as possible to mitigate any extended impact.”
Vallejo says W.A. Rasic crews are utilizing mostly trench shields and aluminum shores to install pipeline over roughly 8-miles of open cut pipeline installation. “We are utilizing beam and plate shafts for tunnel scopes and some beam and lagging shoring systems along various points of the alignment as well. Shoring materials utilized on the project includes steel from our inventory as well as the supplemental use of shoring and steel plate rentals from National Trench Safety,” says Vallejo.
W.A. Rasic’s contract includes several unique elements on this project, some of which require third party coordination and collaboration to meet the needs of the project. “There is a grade separation where a train crossing (North County Transit District) goes under Miramar Road along the main portion of the alignment. Coordination efforts with North County Transit District is centered around multiple 48-hour track closures for work on Saturday and Sunday where W.A. Rasic, and subcontractor, Allied Steel, successfully installed 120 feet of 36-inch pipe to the underside of the overpass and hanging over the railway,” says Plunk.
Plunk continues by pointing out that the 60-inch diameter jack & bores ranged from 150 to 645 linear feet in length. In addition to the four jack and bore tunnels, there are also two 60” diameter microtunnels that were installed on the project by Ward & Burke Tunneling, Inc. One of the micro-tunnels exited in the Miramar Reservoir, which necessitated a wet retrieval process utilizing divers, barges, and cranes to recover the micro-tunnel boring machine (MTBM). The “in-water” retrieval scope was performed by Ballard Marine Construction.
“The two micro-tunneling operations share a joint launch shaft comprised of a shotcrete and girder system designed and installed by Drill Tech Drilling & Shoring. The circular shaft is roughly 95 feet in depth and 40 feet in diameter,” says Plunk. “Both tunnels were launched from this access shaft, with the micro-tunnel underneath Evans
Pond (a small pond south of the reservoir) completed prior to the micro-tunnel going into Miramar Reservoir. Ballard Marine prepared a landing pad comprised of crushed rock at the precise exit location of the micro-tunnel machine (MTBM) entering the lake bottom which was roughly 100 feet in depth. With the landing pad in place, the MTBM entered the Reservoir bottom onto the landing pad where it was secured and lifted from the lake bottom and up onto barges.”
W.A. Rasic, in collaboration with Ballard Marine Construction, are currently installing over a mile of subaqueous HDPE pipeline on this portion of the project. Plunk explains that at the point where the pipeline runs into the lake, there is just over a mile of a subaqueous HDPE trunk line that telescopes down from 54” to 30” in diameter. With the conveyance of the water into the Reservoir, several outlets ranging from 24” to 8” in diameter are installed to allow even distribution of the water throughout the lake.
Plunk admits that there are several challenges with working in and around the Miramar Reservoir. “With the reservoir being a drinking water resource, mitigating potential contaminants and disturbances presents a unique challenge that requires continuous efforts to ensure that water quality is upheld and protected during construction,” continues Plunk.
W.A. Rasic continues ongoing efforts to complete the project by early 2025. Partnership on the project remains in place with the City of San Diego Pure Water project team. The City’s team is led by Richard Fernandez (Senior Construction Engineer), Azin Nour (Construction Manager), and Donnie Purscelley (Resident Engineer). WA Rasic’s progression on the project would not be possible without the leadership and expertise of our General Superintendent, Gilbert Estrada, Site Superintendent, Brandon
Amos, Structures Superintendent, Mark Stewart, Division Manager, Jeremy Juarez, and Site Safety Manager, Genevieve Martinez, as well as all of the dedicated members of our crews onsite.
The North City Pure Water Pipeline is designed to transport 30 million gallons per day (mgd) of highly purified water to Miramar Reservoir for storage. The purified water will undergo chlorination for disinfection and to safeguard the pipelines. Part of W.A. Rasic’s contract is to construct a dechlorination facility which will intercept water being conveyed by the Pure Water pipelines prior to being added to Miramar Reservoir. The dechorlination facility is designed to eliminate disinfectants from the water before it reaches the reservoir, ensuring the protection of plant and animal habitats within the reservoir, and the safety of recreational users who visit daily.
The Pure Water San Diego program will serve to decrease reliance on imported water and exposure to its projected cost increases. It will also decrease ocean discharges and provide consistent water availability regardless of drought or rain. For more information on Pure Water San Diego, please visit Pure Water San Diego Website. For more information on W.A. Rasic Construction, please visit W.A. Rasic Construction website at www.warasic.com or call the corporate office in Long Beach at (562) 928-6111. Cc
