Did you know that, in addition to operating wastewater and solid waste facilities, the Sanitation Districts own and maintain a marshland? Yes, it’s true! There is a 17-acre marshland, called the Bixby Marshland, to the northwest of the Joint Water Pollution Control Plant (JWPCP) near the intersection of Figueroa Street and Sepulveda Boulevard in the City of Carson that has recently been restored by the Sanitation Districts.

What is a marshland?

A marsh is a tract of soft, wet land usually containing grass or rushes. The Sanitation Districts’ marshland consists of various habitats that receive water from the Wilmington Drain. Wetlands are unique because of their role as an “ecotone,” or transition area, between terrestrial (land) and aquatic (water) environments.

Marshland before improvement. Click to enlarge.

How was the Bixby Marshland created?

The Bixby Marshland is a remnant of a formerly extensive, natural freshwater wetland known as Bixby Slough. Due to various development projects, such as the construction of the Harbor Freeway, housing projects, and storm water control projects, Bixby Slough was reduced in size until only the 17-acre Bixby Marshland and the Machado Lake area in the Ken Malloy Harbor Regional Park remain.

To maintain Bixby Marshland, a pump was installed to lift storm water and urban runoff from Wilmington Drain into the marshland. After going through the marshland, the water exits through an overflow structure back into Wilmington Drain.

Why are wetlands important?

Wetland habitats are home to 43 percent of the federally-listed endangered and threatened species. They provide habitat for birds, animals, amphibians, invertebrates, fish, and a diverse group of plants.

Besides providing habitat, wetlands are sometimes called “the kidneys of the landscape” because they receive water that rushes off the land during storms. In the wetland, water is cleansed of sediments and pollutants before it slowly enters the ocean or underground aquifers.

What habitats are present at the Bixby Marshland?

Habitats are groups of plants that all thrive under the same conditions. The Bixby Marshland originally included wetlands, riparian (the area located along the bank of the wetlands), and upland areas. Open water and meadowlands habitats were added to the marshland during the restoration and enhancement process.

Construction underway; note Sanitation Districts treatment facilities shown to the left of this photo. Click to enlarge.

Why did the Sanitation Districts restore and enhance the marshland?

In 1995, the Sanitation Districts completed a Master Facilities Plan and an Environmental Impact Report (EIR) for their large regional sewerage system called the Joint Outfall System, which includes the JWPCP. The Master Facilities Plan called for the construction of large treatment facilities to the east of the marshland. The EIR identified possible degradation of the marshland due to increased runoff from developing this area. To mitigate this impact and improve and maintain the marshland, the

Sanitation Districts prepared a Marshland Management Plan having four goals:

(1) Hydrology: Improve the hydrologic (water flow) conditions to maintain and enhance the freshwater marsh and riparian habitats in the marshland;

(2) Vegetation: Maintain vegetation health and enhance the diversity and amount of native vegetation habitats in the marshland;

(3) Wildlife: Maintain and enhance wildlife habitat in the marshland; and

(4) Public Use and Aesthetics: Continue to control public access to the marshland and maintain its aesthetic function.

Has the marshland management plan been implemented?

The Sanitation Districts began implementing the Marshland Management Plan by working with the Los Angeles County Department of Public Works to improve the water flow through the marshland. The Sanitation Districts cleared the main water flow path through the marshland and the marshland was filled with water taken from the Wilmington Drain. It was soon discovered that the water flow in the marshland went to the far eastern side of the property instead of providing water to the majority of the marshland area. The Sanitation Districts decided that the marshland would have to be reconstructed to improve water flow and better support the habitat.

This conceptual design plan shows the marshland improvements. Click to enlarge.

How was the marshland redesigned?

The new design called for grading the marshland to provide a more centralized water flow pathway and to keep water a safe distance from the nearby treatment facilities. The Sanitation Districts needed to obtain permits from the Regional Water Quality Control Board, the U.S. Army Corps of Engineers, and the California Department of Fish and Game. Because of the amount of vegetation that would be removed by the grading, the Sanitation Districts hired a consultant with the necessary skills and experience to redesign the marshland. After a competitive evaluation process, the Sanitation Districts hired WRA, Inc., a consultant specializing in wetlands.

WRA began by evaluating the marshland to determine an alternative water flow route as well as the health of the vegetation on site. WRA settled on a design where the water meandered through the site with a series of pools. These pools were added to provide open water habitat, which was not present in the original marshland. WRA next evaluated the health of the marshland’s vegetation, and came to three conclusions: (1) non-native vegetation, such as palm trees, eucalyptus, and castor beans, were either co-dominant with native species or, in some areas, had actually crowded out native species; (2) many of the native trees were nearing the end of their life; and (3) the variety of plants at the site was low. WRA recommended that non-native vegetation be removed, the site be graded to provide a more centralized water flow pathway, and a larger variety and quantity of vegetation be planted in the area. This led to the new design for the marshland.

What is included in the new design?

The new design incorporates a meandering stream with several pools and an island for birds. The habitats represented include wetlands, riparian, open water, meadowlands, and upland areas. Native vegetation has been planted throughout the marshland. Several large dead eucalyptus trees were left in place to provide perches for birds. There is an education and viewing area, consisting of a parking lot, walking trails, three overview stations, two shade structures, benches, a display garden with plant identification stakes, and three informational placards.

Construction and enhancement of the marshland took two years to complete. Click to enlarge.

How much did it cost to restore and enhance the Bixby Marshland?

It cost about $2 million to construct and enhance the marshland including putting in all of the new plants.

The Sanitation Districts received a $400,000 grant from the state for the development of the marshland. These funds were made available through Proposition 50, which is dedicated to water improvement projects.

What types of plants are present at the marshland?

The marshland plants are classified according to the areas where they grow. Wetlands plants consist of various types of tules and rushes. These are the plants that grow in up to two feet of water. Riparian plants grow at the edge of the water and can tolerate being flooded for short periods of time. They include willow, cottonwood, and sycamore trees, mulefat, elderberry, and California rose. Upland plants, which grow further away from the water, include box elder, white alder, toyon, and pine trees as well as sage, coyote bush, buckwheat, brittlebush, sumac, monkeyflower, and lemonade berry. Finally, meadowlands contain various native grasses, such as sagebrush, brome, brittlebush, buckwheat, California poppy, deerweed, needle grass, desert fescue, tufted hair grass, spikerush, barley, and wildrye.

Marshland after planting was complete. Click to enlarge.

In the display garden, areas around the parking lot, and along the viewing areas, many of the same plants discussed above will grow, plus manzanita, beach strawberry, gooseberry, yarrow, larkspur, sunflowers, and desert grapes. Plant identification stakes around the display garden will identify the various plants.

What types of wildlife are present at the marshland?

Many birds can be seen at the marshland. Some of the more common ones are various types of ducks, egrets, red-winged blackbirds, red-tailed hawks, black-necked stilts, herons, coots, and sandpipers. Other animals include raccoons, skunks, mice, lizards, opossums, mosquito fish, and toads.

Walkways meander around the marshland property. Click to enlarge.

Is the marshland open to the public?

Beginning in August 2009, the marshland will be open the first Saturday of the month from 8 a.m. - 12 p.m. for anyone interested in visiting. The entrance to the marshland is located on Figueroa Street, just south of Sepulveda Blvd, on the west side of the street. An iron gate, not far from the corner of Figueroa and Sepulveda, leads into the parking lot. Tours for groups are also available by appointment. To schedule a tour, please call
(562) 908-4288, ext. 2301.