CLEANING WATER NATURALLY
Irvine Ranch Water District (IRWD) has a unique program that uses restored wetlands to naturally clean urban runoff from the San Diego Creek Watershed. Water in the creek comes from storm drains in the community and is highly polluted with nutrients from landscaping, pet waste and other contaminants. The water also brings large quantities of sediments with it. If left untreated, these pollutants would flow to Upper Newport Bay.

In 1997, IRWD began voluntarily treating urban runoff by reconstructing wetlands a the San Joaquin Marsh and Wildlife Sanctuary in Irvine. A large portion of the urban runoff in San Diego Creek is diverted into the system of manmade ponds where it flows for seven to 10 days. This gives plants and soils in the ponds time to naturally remove nitrates and other pollutants. The cleaner water is delivered back into the creek to continue its journey through Upper Newport Bay to the ocean.

The San Joaquin Marsh and Wildlife Sanctuary works so well to clean urban runoff that IRWD is expanding the concept to a series of more than 30 smaller wetlands called the Natural Treatment System. These wetlands, constructed throughout the San Diego Watershed in Orange County, direct runoff through one or more wetlands for incremental cleaning before it reaches the San Joaquin Marsh for final polishing. Click on map for an enlarged view.

SEDIMENT REDUCTION
Three sediment trapping basins, measuring five feet deep and 2000 to 3000 feet long, were built in San Diego Creek, adjacent to the IRWD Michelson Water Reclamation Plant in Irvine. These basins trap 50,000 tons of sentiment each year. Phosphorus, a key nutrient for algae growth, is attached to the sediment, and is also trapped in this process.

The IRWD San Joaquin Marsh and Wildlife Sanctuary is located at the end of Riparian View Drive off Michelson Drive in Irvine. (map) The sanctuary is open to the public from dawn until dusk daily and there are 12 miles of walking trails to enjoy. No motor vehicles, bicycles or pets are allowed, to minimize disturbances to the 200 species of birds and other wildlife that reside in the sanctuary. For a San Joaquin Wildlife Sanctuary brochure with more information, call (949) 453-5500 or click here to order one online.