Montevina Water Treatment Plant Improvements Project – Los Gatos, CA

Challenge 

Founded in 1866, San Jose Water Company (SJW) is an investor-owned public utility, and is one of the largest and most technically sophisticated urban water systems in the United States. SJW serves over one million people in its 140-square-mile service territory within the greater San Jose metropolitan area with high quality, life sustaining water with an emphasis on exceptional customer service. SJW also provides services to other utilities including operations and maintenance, billing, and backflow testing. By sharing these services with others, SJW provides a benefit to the local community, lowers the cost of water operations, and improves opportunities.  SJW’s capital improvement program exceeds $100 million annually, and has regularly utilized design-build as a collaborative project delivery method since 2002.     

The Montevina Water Treatment Plant (WTP), located in the foothills south of Los Gatos, CA, is SJW’s largest surface water treatment facility with a treatment capacity of 30 MGD. The existing Montevina WTP utilized a mono media direct filtration process and was over 40 years old. Montevina WTP’s source water comes from various intakes located in the Santa Cruz Mountains. During winter storm events, when abundant water is available, the existing plant could not reliably treat the high turbidity source water to meet current state and federal standards for surface water filtration. In addition, the existing plant lacked tools to manage disinfection byproducts, making compliance with the Stage 2 Disinfectants/Disinfection Byproducts Regulation more challenging. Other water treatment plant processes and support facilities reached their useful life and were in need of retirement and replacement. 

Approach 

In 2010, SJW conducted a feasibility study to look at plant improvement alternatives that addressed the high raw water turbidity challenge as well as the disinfection byproduct compliance and aging infrastructure needs. The feasibility study recommended membrane treatment to replace the existing mono media direct filtration process as well as improved pretreatment and solids handling facilities. Progressive design-build was an attractive delivery method for SJW because of the high level of collaboration and flexibility to modify the scope of the project to fit within SJW’s fixed budget. SJW conducted a two-step procurement process to select their design-builder. An RFQ was followed by an RFP to three short-listed teams. HDR was selected as the design-builder after a proposal review and interview process. 

The plant improvements included an improved flash mix and flocculation process followed by settling basins and a membrane filtration system. Improved solids handling facilities including clarifier thickeners and screw presses for managing residuals were constructed. The project also included construction of a new administration building, water quality laboratory, standby power generation, and site access improvements from the adjacent state highway and county road. The plant improvements will allow SJW to treat water with raw water turbidity levels as high as 100 to 500 NTU during and following storm events. 

Results  

The $50 million project started in 2014 and was completed in 2017. The progressive design-build approach met SJW’s expectations in terms of innovation, collaboration, and flexibility to adjust the scope of the project to meet a fixed budget. HDR and SJW worked together during the 12-month design phase to optimize the project scope by incorporating several innovative ideas into the project such as conversion of the existing filters to plate settling basins, utilizing an existing clearwell for temporary off-spec basin storage during construction, and incorporating a new administration building into the project. Montevina WTP plant improvements will allow SJW to continue to deliver high quality drinking water to its customers, increase the reliability of plant facilities, and reduce SJW’s need for more expensive imported water from other water utilities. 

“The progressive design-build approach used for the Montevina Water Treatment Improvement Project required significant dedication from a small team of internal resources as well as the HDR project team. We are confident, though, that this investment will ultimately result in a project that employs the best technology and process for our project conditions and goals, within the timeframe prescribed in the RFP and within the approved budget. I don’t believe that we would have been able to have that same level of confidence with either a traditional design-bid-build delivery approach or even a conventional design-build approach.” – Craig Giordano, SJW Vice President of Engineering