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San Antonio Water System Brackish Water Desalination Program, Phase I

San Antonio Water System Brackish Water Desalination Program, Phase I - San Antonio, TX

Securing San Antonio’s Water Future

The San Antonio Water System (SAWS) is developing a program that will provide San Antonians with a new water source. The SAWS brackish groundwater desalination project will transform brackish water from the Wilcox Aquifer in southern Bexar County, TX, into millions of gallons of drinkable water using reverse osmosis. The estimated $411 million program, which will consist of three phases, is part of the SAWS 2012 Water Management Plan, designed to meet the city’s water needs over the next 50 years while reducing dependence on the Edwards Aquifer. Brackish groundwater is a plentiful, previously untapped, local source of water that will help diversify San Antonio’s water supplies.

In March 2013, Parsons, with a 50/50 joint venture (JV) partner, was selected by SAWS to serve as the construction manager at-risk (CMAR) for the first phase of this critical brackish water desalination program. This $119 million CMAR contract includes:

  • Performing preconstruction phase services
  • Drilling and fitting out four new production wells
  • Fitting out eight existing production wells
  • Drilling and fitting out one new injection well
  • Fitting out existing injection well
  • Fitting out six monitoring wells
  • Building raw water conveyance system
  • Constructing all program components
  • Constructing and operating treatment plant for 3 months
  • Constructing new administration building

The scope of work includes 12 raw water production wells, raw and finished water conveyance, residual conveyance, a new deep injection well, a 10-MGD reverse osmosis membrane water treatment plant, a chemical treatment system, supervisory and data acquisition controls, and a new administration building that incorporates a public tour route, pilot plant, and training facility.

Project Phases and Milestones

Parsons and its JV partner participated in the design phase of the project by generating milestone constructability reviews and cost estimates. Throughout this phase, we worked with the designers to tailor alternate methods of construction, creating substantial cost savings for the project. In addition, an integrated permitting team of SAWS, program managers, and JV experts quickly obtained all environmental and construction permits to prevent any project delays.

The preconstruction phase was completed in March 2014 and included milestone constructability reviews, permitting, and cost estimates.

Parsons and its JV partner were issued notice to proceed with the construction phase in May 2014, and we mobilized to the site 1 month later. In July 2014, SAWS hosted a groundbreaking ceremony to kick off construction of its brackish groundwater desalination program. Event participants included SAWS trustees and San Antonio Mayor Julián Castro (now U.S. Secretary of Housing and Urban Development) as well as other state and local dignitaries. Construction is now 58% complete, and the first phase is slated for completion in 2016.

Multifaceted Project

As with any project of this magnitude, complex tasks are addressed. For example, soil conditions led to borehole instability. In response, the JV’s subcontractor proposed a slurry method of construction for the drilled pier foundations, using polymer slurry to keep the borehole stable for the entire depth of the excavation. Reinforcing steel was then placed into the slurry, and concrete was injected using a concrete pump beginning at the bottom of the excavation.

The project schedule is also intricate. Public advertising, subcontractor selection, contract awards, subcontract terms negotiations, construction planning, and submittal processing had to occur on a fast-track schedule. The JV created individual work packages for the early critical-path scopes to allow smaller subcontract negotiations and accelerated mobilization and to include more local construction firms in the project.

Process Building Construction

Safety, Diversity, and Technology

The project safety program is proactive and interactive to achieve its safety goal of zero incidents. The safety program includes daily “Take 5” meetings, weekly safety meetings, monthly mass safety meetings, and a host of other activities during which near misses, potential safety hazards, and other safety-related items are discussed. As a result, the project has a record of zero lost time to date.

The project also incorporates a rigorous diversity program. This small minority/women-owned business enterprise (SMBE/SWBE) program maximizes participation and promotes equal opportunity and nondiscrimination. The project has exceeded SAWS’ goal of awarding 17% to SMBEs/SWBEs:  SMBE/SWBE participation is currently at 36%, and there is still a work package to award.

Technology plays a key role in managing this project, and the extensive use of electronic document control increases efficiency. Contract documents are hyperlinked to the referenced detail/section, responses to requests for information are posted electronically, and information is accessible from iPads and tablet PCs in the field.

When completed, SAWS’ plant will be the largest inland desalination plant in the United States. Worldwide, Parsons has successfully constructed 6,000+ miles of water/wastewater pipeline. In the 70 years since Parsons was established, our infrastructure teams have built a well-deserved reputation for providing innovative solutions that meet our customers’ needs on time and within budget.