The Orinda Water Treatment Plant is undergoing renovations, a five-year project, considered the largest dollar project in EBMUD’s 100-year history, with a budget of $341 million.
If you have driven Camino Pablo lately, it’s likely you’ve noticed the 210-foot tower crane at the Orinda Water Treatment Plant (WTP), located between Camino Pablo, Manzanita Drive and San Pablo Creek.
“It’s not something that probably has been seen in Orinda in recent history, and maybe it’ll never be seen again,” said East Bay Municipal Utilities District (EBMUD) Senior Civil Engineer Tim Karlstrand.
The project is the most expensive project in EBMUD’s 100-year history, with a budget totaling $341 million, said project manager Karlstrand. The overhaul is financed by EBMUD through municipal bonds.
The projected construction period runs until spring of 2027.
Big changes are coming to the facility, which was built in 1935 and delivers fresh water to over 800,000 customers daily. The current primary treatment process involves chlorine, which reacts with organic material particles in the water, creating disinfection byproducts.
“We have been within all of the regulations for disinfection byproducts in our water quality, and we even have more stringent internal goals for meeting our disinfection byproduct goals,” said Karlstrand.
“However, we do see the climate changing,” he continued. “We do see water quality challenges emerging in the future.”
The upgrades at the Orinda WTP will implement ultraviolet (UV) light as its primary disinfection method, following filtering. Chlorine will remain a secondary disinfectant, and a new chlorine contact basin will add additional disinfection.
Currently, water travels from the Pardee Reservoir in the Sierra Nevada foothills, is chlorine- treated, filtered and then sent out for distribution, and secondarily disinfected with chlorine to prevent regrowth of pathogens. The shift to UV light will help the public utility prepare for the next century of water-quality challenges, said Karlstrand.
The construction portion of the project has faced some challenges, one being the WTP’s location.
Originally built on centrally located land, “in the middle of the pear orchards out in Orinda,” the city’s desirability as a place to live eventually led to the land around the plant being built up, said Karlstrand.
“We really have very limited real estate at the water treatment plant site to build this project, so it’s very challenging to design and build,” said Karlstrand, explaining that construction is constrained to the area between the creek and the existing plant.
The small footprint has required excavation to 65 feet below the ground surface to build the new facilities. Limited space has also led to building a bridge, and the foundation for an additional bridge, over a portion of the treatment plant to support heavy equipment, materials and supplies, which the original infrastructure cannot.
According to Karlstrand, an older building housing construction offices will remain on the WTP site. EBMUD’s project information and schedule webpage notes that an existing maintenance building will be demolished, and a two-story maintenance and UV electrical building, called MAUVE, will be constructed.
The new UV structure and chlorine contact basin will be below-grade. Other improvements include two electrical buildings, a standby generator, pipelines and vaults, plus other supporting facilities. MAUVE, the UV structure and the chlorine basin will be adjacent and fully integrated facilities, according to EBMUD.
“We’re actually building a majority of the facilities below ground,” said Karlstrand.
Traffic analysis conducted by EBMUD determined there will be a “less than negligible” impact to traffic, which was a concern voiced by Wagner Ranch Elementary School. Students from the school participated in tours of the facility before construction began, learning about the water treatment process and the upcoming changes.
“We’ve been working with the school throughout the project to let them know when we would start having the trucks on the road that hauled soil, which is always this visual signifier to the community that the project started,” said Karlstrand.
EBMUD is also constantly monitoring noise on site, ensuring that it is within the city’s noise ordinance limits.
Speaking on the improvement project’s environmental impact report dating back to 2006, Karlstrand said that EBMUD works to employ a proactive, rather than reactive, approach to projects:
“We plan on very long-term planning horizons to make sure that we can provide reliable and safe water to our customers for the next hundred years… [this] is what we’re looking at.”