Corpus Christi water supply push advances as Harbor Island desal price tag hits $6.2B

Corpus Christi water supply push advances as Harbor Island desal price tag hits $6.2BFacing critically low surface water reservoirs, Corpus Christi Water is rapidly expanding its alternative water supply portfolio through industrial wastewater reuse, groundwater development, and multi-billion-dollar seawater desalination projects.

The Nueces River Authority's Harbor Island seawater desalination project is now projected to cost $6.2 billion, with developer IDE focusing on an initial 50 MGD capacity.

The city has spent up to $50 million to date on its separate Inner Harbor desalination project and is seeking to restructure its SWIFT loan commitment with the Texas Water Development Board.

Industrial effluent reuse is accelerating, with Valero and Flint Hills Resources preparing to take millions of gallons of treated wastewater offline by late 2026.

The city council approved a CMAR contract with Raytek for a conveyance line from the Oso Wastewater Treatment Plant, freeing up an additional 11 MGD of effluent.

The combined capacity of the city's western reservoirs remains at a critical 15.3%, maintaining the need for stage 2 watering restrictions.

With combined western reservoir levels languishing at just 15.3% capacity, the City of Corpus Christi is aggressively advancing a multi-pronged water supply strategy that includes industrial wastewater reuse, new groundwater well fields, and massive seawater desalination investments. During a July 14 water supply update, Corpus Christi Water Chief Operating Officer Nick Winkleman detailed the staggering scale of the region's desalination ambitions. Winkleman revealed that the Harbor Island seawater desalination project, managed by the Nueces River Authority (NRA), is now projected to cost $6.2 billion. The NRA and its development partner, IDE, are advancing 30% design and developing a cost of treated water, which is expected within the next 90 to 120 days. The project will initially focus on delivering 50 million gallons per day (MGD) of a proposed 100 MGD total capacity, with a discharge permit expected by the end of the calendar year. Simultaneously, the city is advancing its own Inner Harbor seawater desalination project, which has incurred between $40 million and $50 million in costs from inception to date. The city has formally requested that the Texas Water Development Board (TWDB) restructure its SWIFT loan commitment for the project. Meanwhile, draft far-field modeling data is slated to undergo an independent review by the Coastal Bend Bays and Estuaries program. To offset immediate potable demand, the utility is leaning heavily on industrial wastewater reuse partnerships. Valero is currently funding and building a conveyance line from the Greenwood Wastewater Treatment Plant to utilize up to 3 MGD of effluent later this year. Flint Hills Resources is also projected to begin utilizing effluent from the Allison Wastewater Treatment Plant by early fall. Furthermore, the city council recently approved a construction manager at risk (CMAR) contract with Raytek to build a conveyance line from the Oso treatment plant to Greenwood, which will free up an additional 11 MGD of effluent water for industrial diversion. Groundwater development continues alongside these efforts, despite regulatory and technical hurdles. The local Groundwater Conservation District recently postponed a decision to aggregate production permits across the Nueces Groundwater Program, though it authorized temporary drilling permits for the Ed Rochelle property. On the Evangeline Groundwater Project, construction crews have installed approximately 10,105 linear feet of a planned 30-mile pipeline. A separate private groundwater initiative by Seven Seas Water Group expects to complete a test well by the end of July. These capital-intensive supply diversification efforts come as the utility defends its rate structure against outside-city-limit ratepayers. An administrative hearing challenging the 2024 and 2025 water rates concluded this week, with a final decision from the Public Utilities Commission anticipated by the end of the calendar year.