Overaa Construction – Sacramento Water Treatment Plants Rehabilitation

Overaa Construction's commitment to teamwork and history of successful projects throughout Northern California make it the ideal fit to perform a massive overhaul to two water treatment plants in the state's capital city.

“Usually the companies that take on work of this size and complexity are large, national companies,” says Jeff Naff, vice president of water and infrastructure projects for the Richmond, Calif.-based company. 

“We are a mid-sized regional company that has its own team of craftsmen, instead of having to pull a team together from all over the country. All of our people have been with us for a long time, which gives us the ability to perform a high-quality and safe project in a complex environment.” 

Founded in 1907, Overaa is a fourth-generation family owned contractor with experience in a variety of project types including energy and power-related facilities, educational buildings and commercial buildings. 

Overaa started work in June 2013 as the general contractor on the $113 million rehabilitation of both the Sacramento River Water Treatment Plant (SRWTP) and E.A. Fairbairn Water Treatment Plant (EAFWTP). The projects – anticipated for a 2016 completion – involve transforming a water infrastructure system built in the 1920s into one of the most advanced systems of its kind in the state.

The projects are a high priority for the city. “A leading indicator of a successful project is when we're working with a client that has a true need for the project we're building,” Naff says. “The leadership of the city is burning brightly on this project – they are very driven to meet their goal to provide safe, reliable, high-quality drinking water for their constituents.”

Necessary Upgrades

Rehabilitation work to the SRWTP includes building a new flocculation/sedimentation basin, a high-service pump station, mechanical dewatering facilities, a granular media filter complex, an electrical substation and pump drives. These upgrades will allow the plant to meet its capacity of 160 million gallons of water a day, which it currently cannot reach because of hydraulic limitations and aging equipment, the city says. 

The EAFWTP will be renovated to increase the reliability of its filtering, sludge dewatering and disposal operations. The city is currently contracting with companies throughout the year to assist them with these functions. The plant is also limited in the amount of water it can divert by the time of the year, flows in the American River and municipal restrictions, Overaa Construction says. 

Improvements to the site include installing five large centrifuges manufactured by German manufacturer Andritz, used to turn muddy water into sludge. Other improvements include adding a sludge-collection system and yard piping. Once complete, the facility will have a capacity of 100 million gallons of water a day. “These improvements will provide the city with the most footprint-effective solution for processing water,” Naff says.

Problem Solvers

Overaa Construction is working with a team of qualified local and national engineers, consultants and contractors to meet the challenge of upgrading the two facilities while they remain operational. 

The construction of the new pump station at SRWTP in particular is proving to be challenging, as it involves the replacement of an 84-inch influent pipe located more than 25 feet below the Sacramento River watertable and up to 40 feet underground. Contractor The Rados Cos. is performing the pipe replacement while submerged, Naff notes. 

The SRWTP upgrades also include driving 2,500 precast piles into its foundation to support the new facilities. “Driving that many piles inside the footprint of an active water treatment plant poses an element of risk,” he adds. “Doing this requires placing huge pieces of equipment around existing operations, so we have to be very cautious.”

Other challenges include installing the filter complex, where water is filtered to meet potable standards. The structure will ultimately require 60,000 work-hours to complete. Overaa is following a plan drafted by Construction Manager MWH Global that establishes the construction sequence. “MWH Global put extra effort into putting together a plan that gives us guidance to what the site constraints are and what needs to be done to build the facility,” Naff says.

One of the construction constraints is related to timing. One of the two existing facilities can be closed for two months a year during periods of lower demand, shifting the treatment capacity. Recent severe drought conditions raised concerns about the city's ability to temporarily shift demand, as the levels of both the Sacramento River and American River have been extremely low, he adds. 

Overaa is working closely with MWH and other project team members including design engineer Carollo Engineers and electrical contractor San Joaquin Electric to overcome timing and other site challenges. “A project like this requires an extraordinary relationship between the contractor, the plant operator, the construction manager and the design engineer,” Neff says. “We're all coming up with solutions to common challenges together.” 

A Safety Leader 

A strong corporate focus on safety is also helping Overaa make the water treatment plant upgrades without posing a danger to existing personnel or operations. “Everything we do is conscious of safety,” Neff says. The company's EMR rating in 2012 was .76.

Overaa employs five full-time safety coordinators, who lead ongoing training and safety planning efforts across the company. Site superintendents lead weekly meetings at each project location. Additionally, site-specific planning meetings are also common. All employees participate in on-site and off-site safety training courses.

An incentive and award program rewards positive behavior among employees. 

“We have learned that positive reinforcement through incentives can play a big part in the success of our safety program, and safety performance is factored into every superintendent's project bonuses,” the company says. “In addition, our job-specific incentive program is customized to fit the project tasks and duration. We track results through regular meetings; foremen are held accountable for each incident at the job site.”

Incentives for employees who demonstrate safe behavior include cash, gift certificates and t-shirts. Additionally, diamond belt buckles are awarded annually to employees who work more than 1,500 hours without an injury. 

The company's safety program was recently recognized by the state's OSHA, which invited it to participate in a voluntary construction industry protection program. “We are proud to be recognized as a leader in the construction industry for worker safety and health,” the company says. “This is a tremendous accomplishment when you consider how much work Overaa self-performs each year. It is not unusual for Overaa to self-perform in excess of 100,000 man-hours of work on a single significant project or to self-perform as much as 700,000 man-hours company-wide over the course of a year.” 

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