Desalination pilot starts this summer; council presses for modeling results and broader water strategy

City staff briefed the council on progress at the Inner Harbor Water Treatment Campus — the city’s seawater reverse‑osmosis project — outlining demonstration‑plant steps this summer, the timing for modeling and regulatory review, and an accompanying communications plan.

Brett Benhazel, director of the program management office, said the project is working in phases. Phase 1a is near completion with a June 1 target for deliverables including a basis‑of‑design report and an early cost model; staff will present that cost range to council in July. Phase 1b began in April and focuses on further design, long‑lead procurement (notably high‑voltage transformers) and demonstration planning. Construction is slated to start in early 2026 with completion of the project’s major construction in 2028; Kiewit would operate the plant during a one‑year handover before the city takes over operations.

Benhazel described the demonstration plant that will be built on port property. Water will be taken from the Inner Harbor Ship Channel, treated through dissolved air flotation and ultrafiltration, then reverse osmosis. The plant will produce a product water stream and a brine stream, both returned to the Broadway Wastewater Treatment Plant for final handling during the demonstration.

GHD (subcontractor to Kiewit) will perform near‑ and far‑field hydrodynamic modeling required by the Texas Commission on Environmental Quality (TCEQ) to support diffuser design and permit conditions. Benhazel said the model domain extends roughly 7.2 miles west of the discharge and about 1.5 miles east; the modeling will evaluate key variables including dissolved oxygen and stratification to assess local hypoxia risk. GHD will submit modeling work in May with an internal review in June and a presentation of results to council in July.

Benhazel described a pilot timetable: construction of the pilot demonstration equipment and the discharge line is to start in June, with plant start‑up in July–August. The TCEQ requires a continuous 30‑day demonstration run; staff expect to begin that 30‑day continuous operation in September or October and then decommission the temporary equipment and deliver a feasibility report to TCEQ.

Drew Molly, chief operating officer, briefed the council on alternative water‑supply projects being advanced in parallel. He said the city has engaged Garver as a consultant to evaluate multiple options and to accelerate business‑feasibility work; the city expects a business‑case update for several projects in early June with a June 10 memo to council and follow‑up briefings on June 10. Key updates included:

- Nueces River groundwater wells: Six wells are at various stages — one well produced roughly 1,100 gallons per minute (about 1.5 million gallons per day) during startup; other wells were pump‑tested at flows up to 2,000,000 gallons per day. The city submitted a temporary bed‑and‑banks permit application to TCEQ and delivered a letter to the governor’s office; staff said a two‑to‑three‑week initial review is expected if TCEQ does not request additional information. The temporary permit, if granted, would allow use for up to three years.

- Evangeline and EV Ranch projects: The city team is evaluating these potential brackish groundwater supplies and intends to include them in the regional water plan so they can be eligible for state funding programs (for example, SWIFT through the Texas Water Development Board). Garver was engaged to evaluate business feasibility, with an aggressive schedule targeted for a June 2 preliminary business case and a June 10 council briefing.

- South Texas Water Authority / 7Seas: Discussions are ongoing with the regional authority and county partners; staff said permitting and construction for a large desal/transmission project would be a longer‑lead undertaking (likely measured in years, not months).

Alisa Olson, the city’s communications director, presented a three‑part public education program for the Inner Harbor project and the broader water strategy. The components are: (1) a local awareness campaign for the Inner Harbor project that uses paid social, Google search and display ads and radio; (2) a statewide education campaign in partnership with the Texas Tribune timed to the legislative session (cost reported to council as $30,000); and (3) a local campaign explaining the city’s four‑tier water approach (seawater desalination, pipeline expansion, lakes/reservoirs and groundwater wells). Olson said the local “What fills your cup” campaign budget was about $49,995 and the four‑tier campaign budget approximately $43,000, for a total near $123,000 across the three campaigns to date.

Council members repeatedly pressed staff for context: several said the city should lead with a multi‑source water message rather than focus primarily on the Inner Harbor, and some questioned the timing and scale of paid communications before final cost and financing decisions. Councilwoman Kalyn Paxton and others asked that staff emphasize conservation and include a clear inventory of costs and firm yields for all water sources. Council agreed to continue twice‑monthly briefings on the Inner Harbor and to receive regular written updates on alternative supply projects.

The council also heard that the city is using a progressive design‑build approach and that more detailed guaranteed maximum price development will follow. Staff said they will return with modeling results, demonstration‑plant outcomes and the basis‑of‑design cost range in the coming weeks.