Project Update – June 2007

The Natural Treatment System (NTS) is a plan to construct 31 water quality wetlands to help clean urban runoff in central Orange County and to improve water quality in Upper Newport Bay.

Over the last four decades, large portions of central Orange County have transformed from farmland and open space to a bustling urban environment that supports all the activities of the hundreds of thousands of people that live there. That transformation is expected to continue in the decades to come. Fortunately, planners anticipated the impacts of this urbanization and have taken innovative measures to minimize those impacts and provide a healthy, sustainable community with high quality of life.

A new innovation is development of a network of wetlands throughout the area to treat the water that runs across the urban landscape before it reaches Upper Newport Bay downstream. In Southern California, the bay is one of the last remaining estuaries where freshwater and ocean water mix to provide a lush habitat for hundreds of species of plants, birds, fish, and other wildlife.

The NTS wetlands use natural processes to remove the various pollutants that are picked up by urban runoff, including fertilizers, pesticides, bacteria, automobile fluids and brake linings, and trash.

To date, projects already in service include the San Joaquin Marsh, Sand Canyon Reservoir, Rattlesnake Reservoir, Quail Springs, Quail Meadow, Old Laguna Canyon, and Turtle Ridge. IRWD is under construction on in-line basins in Peters Canyon Channel, Santa Ana/Santa Fe Channel, and San Diego Mainstem Channel, and an off-line basin at El Modena Park. Approximately 15 other basins are in various stages of design/construction and will be in service within two years.

IRWD, in partnership with the City of Irvine, is also under construction on a specialized subsurface wetland, the Cienega Filtration Project (Cienega), which is designed to remove selenium from surface water in Peters Canyon Channel. Upon successful completion of this first installation, Cienega will be expanded to treat additional flows. It may also be a promising technology for application elsewhere in the arid western United States where selenium is present.

While IRWD is responsible for the construction and operation of NTS, much of the success of NTS is in the cooperative effort among IRWD, the County of Orange, cities, water quality regulators, wildlife officials, landowners, and the public.

IRWD has already proven the success of wetlands for the treatment of urban runoff at its San Joaquin Marsh. The Marsh and the NTS basins not only provide effective urban runoff treatment, but also provide rich habitat and valuable open space right in the middle of one of the most densely populated areas of the nation. Situated just a mile upstream of Upper Newport Bay, the Marsh is world-renown in its own right for its exceptional bird watching.

Come take a stroll at the Marsh to see what NTS is bringing to local neighborhoods.