California's Water: Facts on "Cleaning Water the Natural Way "

Background

Wetlands have always been a key ecological resource in California. They provide habitat for thousands of species of aquatic and terrestrial plants and animals. Migrating birds rely on wetlands for rest and food during their long journeys, and many use them as nesting sites as well.

But wetlands do more than provide habitat. They play a key role in cleaning urban runoff by removing nutrients, sediment and pollutants from water before it reaches estuaries, bays and other sensitive ecosystems. In a sense, wetlands are nature’s own water filtration systems.

Unfortunately, California has lost as much as 95% of its natural wetlands over the decades as the state has developed. As a result, we are missing out on nature’s ability to clean and naturally filter out pollutants from urban runoff before it reaches our bays, our beaches and the ocean.

Luckily, many local water agencies are seeking to change that through collaborative efforts to restore wetlands. By acquiring and reconstructing natural wetlands areas, local agencies are helping to recreate nature’s way of cleaning water, while at the same time providing valuable habitat for species and new recreational and education opportunities for their communities.

Central Points

• Wetlands serve a number of important purposes
• Through innovative partnerships, agencies are restoring wetlands and in the process improving water quality, habitat and other ecological values
• These projects represent a win-win for the environment, the local agencies and their communities.
• Water agencies are using a unique mix of high-tech methods and proven natural techniques to allow wetlands to clean urban runoff and better protect bays, beaches and the ocean.

The San Joaquin Marsh in Irvine

In the late 1960s, the Irvine Ranch Water District (IRWD) constructed its Michelson Water Reclamation Plant in the area, although the surrounding land continued to be owned and farmed by The Irvine Company.

In 1995, the district purchased the remaining 320 acres around its Michelson Water Reclamation Plant, and IRWD officials saw the perfect opportunity to use the newly acquired land to reconstruct wetlands in the area. Several rectangular dock ponds were configured to more closely resemble natural ponds and to restore the natural filtration process associated with wetlands.

Today, the flow-through system allows water from San Diego Creek (which receives water from urban storm drains) to be pumped into the wetland ponds. There, the water slowly moves through the ponds for seven to 10 days. During that time, the water comes into contact with cattails, bulrush and other vegetation that helps remove 50% to 70% of the nitrogen in the water. Nitrogen typically comes from fertilizers and landscape over-watering. Too much nitrogen in local streams can lead to algae blooms in Upper Newport Bay, resulting in lower oxygen levels for fish and other aquatic species.

The water quality benefits of San Joaquin Marsh have worked so well over the past seven years that Irvine Ranch Water District is now working to build 31 smaller wetlands throughout the San Diego Creek watershed. The first four sites of the project have already been completed and planted with native vegetation, and design work is under way on the additional sites. The project is called the Natural Treatment System.

The marsh is also the site of IRWD’s San Joaquin Wildlife Sanctuary, which is home to more than 200 species of birds and other wildlife. Blue heron, egrets, tree swallows, black skimmers and a variety of ducks are commonly seen. The sanctuary’s 12 miles of walking trails attract bird watchers, wildlife photographers and others seeking to enjoy this unique setting in the midst of an otherwise urban area.