COASTAL BRACKISH WATER TREATMENT PROJECT

Seawater intrusion in the southern Oxnard Plain has long been a problem due to agricultural, industrial, and residential land uses that rely on groundwater. When pumping exceeds recharge, water levels in the groundwater basin can fall below sea level, drawing seawater into the aquifers and impacting water quality.

Unlike coastal Los Angeles and Orange County, Ventura County has no seawater intrusion barrier in place, and the sea impairment renders the groundwater useless for agricultural or municipal uses.

To protect groundwater supplies, United Water is planning a project in collaboration with the United States Navy that will provide a barrier to seawater using extraction wells for hydraulic control and reverse osmosis to treat the brackish groundwater. The project will create as much as 20,000 acre-feet per year of advanced treated β€œnew” water.

The project will reduce groundwater pumping, prevent seawater intrusion into groundwater basins, create an additional irrigation and emergency supply, and is estimated to conserve enough drinking water to supply about 40,000 families for a year.

EXISTING WATER USE IN THE OXNARD PLAIN

PRELIMINARY PLANS HAVE IDENTIFIED
TWO OPTIONS:

EXTRACTION BARRIER CONCEPT: Use coastal extraction wells to create a groundwater depression; water would flow toward wells from all directions and, if the extraction rates are sufficient, seawater should not advance inland past the wells.

The brackish water would be treated and put to beneficial use and the residual brine would be disposed of in the Salinity Management Pipeline (SMP).

INJECTION BARRIER CONCEPT: Surround areas of degraded water quality with a dense array of injection wells and inject enough water to create a groundwater ridge or divide to prevent further intrusion.

The project offers important collaborative opportunities with regional partners, including the U.S. Navy, the Port Hueneme Water District, Calleguas Municipal Water District and Fox Canyon Groundwater Management Agency.

VIEW THE FEASIBILITY STUDY

TYPICAL REVERSE OSMOSIS TREATMENT TRAIN

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TYPICAL REVERSE OSMOSIS TREATMENT TRAIN

LATEST UPDATES

Allocations, Conjunctive Use & Optimization

JUNE 2020 – PRESENTATION
This presentation provides updates on coastal brackish water treatment.

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Brackish Groundwater Treatment

NOVEMBER 2019 – PRESENTATION
This presentation details how extraction wells will limit further salt water intrusion into the basin by treating brackish water to reduce salinity, thereby creating a new source of freshwater.

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