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Irvine’s San Joaquin Marsh and Wildlife Sanctuary

With everything that is happening in the world, we need down time, preferably in a place that helps take away the stress of the day and quiets the mind. Irvine Ranch Water District’s San Joaquin Marsh and Wildlife Sanctuary is just that place.

The area offers a quiet respite in the heart of Orange County’s bustling urban environment. Nearly two-thirds the size of New York’s beautiful Central Park, the Marsh is actually one of Southern California’s most significant freshwater coastal wetland habitats, with more than 300 acres of lovely views, framed by willow, alder and cottonwoods. Not to mention impromptu visits by more than 200 species of birds!

Wendy Haase, senior director, Destination Irvine, describes the sanctuary as a little “oasis” in the middle of the city. “As a runner, I’ve incorporated the two-mile route into my workouts as a way to escape traffic. It’s such a tranquil surrounding.”

Courtesy of Irvine Ranch Water District

Ian Swift, Irvine Ranch Water District’s natural resources manager, talked to Irvine Weekly about the array of fun activities one can do at the sanctuary as well as its history:

“Visitors can walk along 12 miles of trails, relax on benches overlooking scenic marshland, do some birdwatching, take a peek at the butterfly garden and take advantage of the many educational opportunities offered there.”

Swift manages the Natural Treatment System, which is made up of a network of small marshes located throughout our watershed.

The marsh’s Natural Treatment System process occurs in a series of ponds, many of which are configured with islands to provide a secure place for birds to build nests and lay eggs, safe from predators. The nesting islands are surrounded by “predator rings,” which are moat-like structures that remain filled with water even when the level of the main pond is lowered.

Restoration and enhancement of the San Joaquin wetlands was initiated in 1995, partly in response to the effects of fertilizer in local runoff, which had created huge algae blooms in the Newport Back Bay. The marsh restoration was completed in 1998, and the San Joaquin Marsh Campus opened in January, 2009. Nowadays, in addition to providing native habitat and cleaning local runoff before it makes its way to the ocean, the Marsh Campus serves as a historic and educational center.

The Irvine Ranch Water District restored three historic farm homes, one of which was built in 1904 by the Cook family. This was the first house in Orange County to have running water.

“You would think that with so much beauty, Irvine residents would be flocking to the sanctuary. But one of the biggest challenges is getting people to know that it’s there,” acknowledged Swift, who has worked for the sanctuary for seven years.

Courtesy of Irvine Ranch Water District

“Many people call this the ‘hidden gem’ of Orange County,” he said. “We’d like to see more people taking advantage of it and all that it offers to the community.”

The marsh is home to hundreds of insects, reptiles and mammals, including white pelicans, great blue herons, cormorants, ducks and egret. Visitors may also spot a western fence lizard, harlequin bug, raccoon, cottontail or bobcat!

Special attention is placed on the 140 nesting boxes situated throughout the marsh. Sea & Sage Audubon Society volunteers look for nesting activity and count the eggs and monitor the hatchlings. Throughout the nesting season – late spring through early fall – there could be two or three broods of eggs laid and hatched in a single occupied nesting box.

One of Swift’s favorite memories was the recent discovery of breeding Wilson’s warblers in the riparian woodlands. “This species has not been recorded in coastal Orange County since the early 1990s,” he told us.

Also, most of the plants at the marsh were selected based upon botanical records of the native plants which were historically present in Central Orange County 150 years ago, including penstemon, sage, San Diego coyote mint and buckwheat.

“A pollinator’s garden was established in 2016 to attract native bees, bumble bees, sweat bees, butterflies, moths, beetles and other indigenous insects that help plants produce seeds by transferring pollen grains from flower to flower,” he added.

The sanctuary is a unique place for families to come for a day, to learn more about the environment and animals residing in the area. Swift described the marsh as a “living laboratory” for students, teachers and the public.
“Irvine Ranch Water District, in cooperation with DiscoveryCube and Sea & Sage Audubon, offers a variety of water- and wildlife-themed educational programs and tours, including an active school field trip program that serves thousands of students a year,” said Swift.

Courtesy of Irvine Ranch Water District

In addition, Sea & Sage Audubon operates a visitor’s center at the Marsh and assists with self-guided and guided tours and educational programs for the public. Some of their scheduled programming includes birding classes, bat walks, summer camps and junior naturalist programs.

Apart from the educational and recreational opportunities available at the San Joaquin Marsh, the wetlands are a critical component of IRWD’s Natural Treatment System, which captures and cleans water runoff flowing from the San Diego Creek into the ocean, noted Swift.
“This system of ponds and native plants naturally clean urban runoff from the San Diego Creek and helps to protect the environmentally sensitive Upper Newport Bay,” he explained. “This runoff is captured in the marsh, where it interacts with the bulrush and other plants for seven to 10 days.”

During that time, up to 70 percent of the nitrogen is removed to help keep the ecosystem in balance. “The cleaner water is returned to the creek to continue its journey to Upper Newport Bay and the ocean,” Swift added.

And would you believe, a whopping 50,000 tons of sediment and 10,000 pounds of phosphorus are removed each year from San Diego Creek desilting basins that were built in the late 1990s?

The marsh is open every day from dawn until dusk, and is free to the public. Visitors should enter the marsh from Campus Drive and Riparian View in Irvine. There is a free monthly Wildlife Walk at the sanctuary on the first Saturday of the month at 9 a.m.

Volunteer naturalists share their love of nature with others to help promote an understanding and appreciation of the wetlands to both wildlife and people.

For more information, visit: irwd.com/san-joaquin-marsh or seaandsageaudubon.org/SJWS/sjws.htm

5 Riparian View, Irvine, CA  92612