Oxnard’s GREAT Program For Groundwater

The City of Oxnard won an Award for Excellence for this project in the Planning and Environmental Quality category of the 2005 California Cities Helen Putnam Award for Excellence program. For more about the award program, visit www.cacities.org/helenputnam.

Like many California municipalities, the City of Oxnard faces a number of challenges related to water resources, including a growing population, greater demand on water supplies, reductions in groundwater, more costly and less reliable imported state water, and the need to restore local wetlands.

As a result, Oxnard developed the Groundwater Recovery Enhancement and Treatment (GREAT) program. An innovative project with significant regional benefits, the GREAT program combines wastewater recycling and reuse; groundwater injection, storage and recovery; and groundwater desalination to provide regional water supply solutions to the Oxnard Plain. Designed to meet the city’s water supply needs through the year 2020, the program also initiates the delivery of recycled water for agricultural irrigation and groundwater recharging, and provides a brackish water byproduct that can be used to help restore vital local coastal wetlands.

The GREAT program began at the Oxnard Wastewater Treatment Plant with the construction of the Advanced Water Purification Facility (AWPF). This project includes tertiary treatment facilities to meet the state Department of Health Ser-vices criteria for unrestricted reuse and advanced treatment.

Using Recycled Water Innovatively

The treated, recycled water from the AWPF will be made available to agricultural users in the Oxnard Plain that are currently being served by the United Water Conservation District (UWCD), Ocean View Municipal Water District and Pleasant Valley County Water District. This recycled water will be of higher quality than the existing groundwater and will help relieve over-drafting of the local groundwater basin, which has led to seawater intrusion. In the winter, when irrigation demands drop off, the recycled water will be injected into the groundwater to reduce the potential for seawater intrusion into nearby agricultural areas.

By using recycled water in lieu of extracting groundwater, the unused groundwater allocation will be transferred from agricultural users to the City of Oxnard. The city can then extract the groundwater in less sensitive areas, either at its own wells or through UWCD’s El Rio facilities.

Groundwater Desalter

The GREAT program’s groundwater desalter, currently under construction, should be completed in early 2007. The desalter will utilize reverse osmosis treatment technology to produce extremely high-quality potable water to be blended with Oxnard’s local groundwater sources for customer delivery. Initially, the desalter will be capable of producing 7.5 million gallons of water per day with an eventual capacity of 15 million gallons per day.

As a public service and educational benefit, the desalter facility will include a visitor’s center to enable guests to view the water treatment process.

Restoring Local Wetlands

The GREAT program’s Membrane Con- centrate Pilot Wetlands Project was created to demonstrate the environmentally safe use of membrane concentrate to restore coastal wetland ecosystems. The membrane concentrate is similar to brackish water found within these estuaries and may be a suitable water source to help restore the Ormond Beach wetlands.

The project included the construction of six different types of experimental test wetlands, using membrane concentrate from a reverse osmosis facility to determine sustainability of wetland vegetation. Deep and shallow marshes were constructed to emulate native brackish marsh communities. Submerged aquatic vegetation beds were made to imitate open water habitat.

Positive first-year results successfully demonstrated the viability of wetland-based concentrate reuse. Plant growth was found to be normal, vigorous and composed of native plants. Shallow marshes and vertical flow wetlands were dominated by saltgrass and yerba mansa. Deep marshes were dominated by native bulrush. The subsurface flow marsh was dominated by yerba mansa, pickleweed and jaumea, all native California salt marsh plants. The wetlands project shows promise as an environmentally sound approach to restoring valuable wetland resources.

Working Together Produces GREAT Results

Oxnard’s GREAT program provides significant regional benefits as well as measurable enhancements for Oxnard residents and surrounding communities. The program is an excellent example of how challenges can be transformed into opportunities to better serve residents, seek innovative technological means to generate solutions, facilitate partnerships, build public awareness, enhance public confidence and advocate for legislative support.

The development of the GREAT program was made possible through a cooperative effort with partner agencies throughout the region. Years before the program was publicly unveiled, representatives from the City of Oxnard, Port Hueneme Water Agency, United Water Conservation District, Calleguas Municipal Water Agency and Fox Canyon Groundwater Management Agency met regularly to discuss regional water supply issues. The ongoing communication has been vital to the program’s overall success.

Congresswoman Lois Capps of California’s 23rd District introduced legislation to authorize a federal partnership for the GREAT program. The City of Oxnard Water Recycling and Desalination Act of 2004 authorized the secretary of the interior to participate in the design, planning and construction of the GREAT program.

The GREAT program’s comprehensive public awareness campaign has been well received and widely reported in regional news and industry publications. It includes educational videos, community presentations, public tours of the Membrane Concentrate Pilot Wetlands Project, informational brochures, special events and a project link on the Water Division’s interactive website, www.oxnardwater.org.

Contact: Ken Ortega, water superintendent, City of Oxnard Water Division; phone: (805) 385-8139; e-mail: ken.ortega@ci.oxnard.ca.us.

This article appears in the July 2006 issue of Western City
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