Corpus Christi advances $978m Inner Harbor seawater desal plant with Acciona-MasTec JV

Corpus Christi advances $978m Inner Harbor seawater desal plant with Acciona-MasTec JVFacing severe drought and single-digit reservoir levels, the Texas city is moving forward with two major desalination projects, including a 30 MGD seawater facility that promises a 25% cost reduction over previous estimates.

City Council authorized negotiations for a design-build contract with Corpus Christi Desal Partners (CCDP) for the 30 MGD Inner Harbor Seawater Desalination Plant.

The revised proposal estimates total project costs at $978.8 million, down from a previous $1.2 billion estimate under a former contractor.

A Phase 1 contract, expected in April, will cover 60% design and a $12 million demonstration plant at a combined cost of $78.6 million.

In a separate move, the council approved a $43.5 million contract with FCC Aqualia for a containerized brackish water desalination plant.

The City of Corpus Christi, Texas, is aggressively expanding its desalination portfolio in response to a severe drought that has left its combined reservoir levels at just 9.5%. At a February 24 meeting, the City Council voted to advance negotiations with Corpus Christi Desal Partners (CCDP)—a joint venture of Acciona Agua Corporation and MasTec Industrial Corporation—for the Inner Harbor Seawater Desalination Treatment Plant. The 30 million-gallon-per-day (MGD) facility is now estimated to cost $978.8 million. This represents a roughly 25% reduction from a prior $1.2 billion estimate developed during a previous 10% design phase by a former contractor. CCDP achieved the projected savings through design optimizations, including reducing the number of reverse osmosis trains from seven to six, eliminating two storage tanks, and utilizing Acciona's proprietary ACTIDAF (dissolved air flotation and media filtration) pretreatment technology to reduce the facility's footprint. Acciona brings extensive experience to the project, having designed and built seawater reverse osmosis plants with a combined capacity of 1,849 MGD. The company currently operates 25 seawater desalination facilities worldwide, including the similarly sized 29 MGD Tampa Bay Desal Plant, the second largest in the United States. The council's recent vote does not authorize immediate capital spending, but directs city staff to negotiate a contract that will be brought back for approval in April. That upcoming Phase 1 agreement, estimated at $78.6 million, will fund the facility's design up to 60%, establish a guaranteed maximum price (GMP), and construct a $12 million demonstration plant required by the Texas Commission on Environmental Quality (TCEQ) for permitting. If the GMP is approved by April 2027, the city anticipates the facility will begin producing water by the end of 2029. Annual operating expenses are estimated at $32 million, resulting in a project water cost of $8.05 per 1,000 gallons. Corpus Christi Water Chief Operating Officer Nick Winkleman noted the city also plans to issue a request for proposals for a long-term operations and maintenance agreement for the plant. The Inner Harbor project continues to face significant public pushback over its location near the Hillcrest neighborhood and concerns regarding brine discharge into a semi-enclosed bay system. To address environmental concerns, the city is conducting parallel far-field modeling to assess potential impacts before finalizing the GMP. In a separate consent agenda item, the council also approved a $43.5 million contract with FCC Aqualia USA Corp. for the design, procurement, and operation of a containerized brackish water desalination plant at the O.N. Stevens Water Treatment Plant. The measure also authorized up to $120 million in emergency construction contracts for a pump station and conveyance system to deliver raw water from the city's Western Well Field.