Clean water for Coloradans
Every time a Denver Water customer makes a cup of coffee or takes a shower, they can thank a new source of reliable water treatment.
After eight years of design and construction, the Northwater Treatment Plant came online in May 2024. The plant is located near Golden, Colorado, on Denver Water’s Ralston Reservoir site. It has a capacity of 75 million gallons per day (MGD) and is expandable to 150 MGD.
One of four potable water treatment plants in the Denver Water system, Northwater is part of a larger program to upgrade the existing North System that dates to the early 1930s. The new plant ensures that the 1.5 million customers in the Front Range will have clean water for many years to come.
Finding a solution
Efficiency, reliability and sustainability are at the heart of the new facility built by Kiewit Infrastructure Co. as part of its Construction Manager at Risk (CMAR) contract with the Denver Board of Water Commissioners. The team self-performed all the yard pipe, process mechanical work, site finishes and startup.
It was a steady, if long, road to the finish line for a project that began in 2016. Early in the preconstruction phase, Denver Water approached the team to ask if the plant could be designed as a 100 percent off-the-grid facility, able to sustain itself without drawing from the power grid.
Kiewit was charged with staying in the parameters of the contract yet aiming to give the owner a solution as close as possible to its vision, said Project Manager Travis Baumgartner.
“As a CMAR, we’re there to help Denver Water value engineer better ways to do things — how do we make the schedule better, how do we make the cost cheaper?” Baumgartner said.
The Kiewit team focused on collaboration. They held regular executive partner meetings with Denver Water to ensure project leadership was aligned and driving toward shared, common goals. Weekly discipline-specific task forces were conducted throughout construction to drive solutions, make decisions at all levels and improve submittal and information request turnaround times. Kiewit also introduced the Decision and Resolution Tracking (DART) process to the project, which drove early visibility of quantity, cost and schedule implications of each
design decision.
Kiewit tailored its original plan to satisfy Denver Water said Colin Bunker, assistant project manager.
“We had very good processes set up. As the owner team was going through key decisions, we were supporting with cost evaluation, schedule evaluation and, at the same time, adding content to its technical evaluations,” he said.
After much consideration, including running many different scenarios about what those solutions could look like, Kiewit and the owner landed on a solution that met the owner’s goal of being sustainable and budget friendly.
“We got the highest sustainability certifications that you can get for both the campus and on-site administration building,,” said Pete McCormick, Denver Water project manager. “That makes Northwater one of the most sustainable and decorated treatment plants in the country, definitely the only one in Colorado.”
Innovative software solutions
When construction started in 2018, Kiewit recommended the use of InEight Document to manage all document controls and workflows project wide. Due to the project’s complex team and GMP structure, the software needed some additional features to meet the job’s overall needs. Kiewit deployed resources to the job site to brainstorm improvements with the client, which led to InEight ultimately making 50 software enhancements that made a significant, positive difference. Kiewit provided on-the-job training to ensure everyone was able to navigate and use the software effectively.
They also implemented the “close-as-you-go process.” On water projects of this magnitude, the client and its representatives typically spend a year or more after final completion collating and archiving project quality, financial and contractual records. With close-as-you-go, records were archived to the client’s database upon reaching partial substantial completion. Due to these early efforts, and InEight’s module integration for Completions, Contract, Change and Document, the archival process was simplified and expedited — resulting in full archival into the client’s system prior to final completion.
Prioritizing Sustainability
Sustainability was a priority for the owner. Kiewit implemented three important elements to achieve that goal:
- Ultraviolet disinfection (UV) — By introducing UV into the treatment process, the need for a disinfection contact basin was eliminated and replaced by a buried, 120-inch diameter contact pipeline, which led to less overall concrete needed on the project.
- A hydroelectric generator — When the plant and hydrogenerator are running, the generator creates more energy than the plant needs annually and the remaining electricity can be distributed to the existing power grid.
- Plant layout — The team made use of the natural slopes of the plant’s foothills location where the major structures were buried, reducing the amount of energy required to heat and cool them year-round. The layout also resulted in the ability to reuse all excavated materials, reducing off-site hauling.
In another nod to the future, the plant is set up to be operated remotely, using a high-performance human-machine interface. Northwater is the first of Denver Water’s existing plants to use the technology.
Built in 2019, the filter building houses seven deep-bed, dual-media filters that make Northwater more resilient to changes in influent water quality. The walls of the building are 3 feet thick.
The plant also contains a 3,500-kilowatt diesel generator for emergencies. The main electrical building serves as the hub for incoming medium-voltage power to the entire plant.
The filter and pretreatment buildings were the two largest structures on-site and drove the critical construction path.
Building into the natural slopes of the hillside provided for a reduction in the heating and cooling energy required for the plant. It also allowed for all excavated materials to be used at the job site.
Valuable in-house assistance
The project also showcased the depth of in-house resources Kiewit can offer clients and what a gamechanger that can be for the project schedule, said Boyd Dunham, construction manager.
During concrete placement, the team noticed some cracking. Kiewit’s concrete experts were brought in to troubleshoot the issue. Together, they rolled up their sleeves, set up a thermal testing plan for the remaining pours, tweaked the mix and poured sample panels.
“Anytime we needed support on specialized things like that, the Kiewit team jumped on it in a hurry,” Dunham said. McCormick emphasized Denver Water’s appreciation of the wide-reaching expertise, tools and resources that Kiewit brought to the project. “At the end of the day, it’s all about people, and we’re fortunate that we have had such great people from Kiewit on this assignment for the entire project.”
Kiewit’s in-house team delivered expertise when the initial concrete pours needed adjustment, creating and testing a new mix in just a few weeks.The pour pictured above was performed by subcontractor Garney Construction.
Flocculation basins are connected by concrete baffle walls with sedimentation basins.
Together, they capture and remove sediment and debris prior to filtration. Northwater features three floc-sed trains each capable of treating 25 MGD, with provisions for future expansion.
Celebrating startup
When it was time to test the water treatment process and bring Northwater online, Kiewit and Denver Water worked together to ensure the process would go smoothly. It ended up being a model for how to do a startup well, explained Startup Manager Jeremy Trujillo.
“Even from day one when we started testing some of the equipment, a lot of their operations and maintenance folks were involved. They were able to ask the vendors questions and really get to know and own their equipment.” Trujillo stated.
This collaborative approach fostered a sense of teamwork and camaraderie between client and contractor. According to Trujillo, after the project officially went online, there was a sense of celebration in the air.
