Wetlands

The Peyton Slough Marsh Complex

McNabney and Moorhen Marshes

Marsh-WrenMt. View Sanitary District’s (MVSD) treated effluent flows into a series of marshes, rather than a deep-water outfall as most treated wastewater does. These marshes, enhanced by the reclaimed effluent, are rich and diverse in wildlife and easily accessible to students, birders, researchers, and the general public. Biologists have identified 116 bird species 69 plant species, over 20 mammals and at least 34 species of aquatic invertebrates making their homes in the wetlands. At least 15 species of birds use the marsh complex for nesting.


RuddyDuckMoorhen Marsh is a 21-acre constructed wetland, the first wetland on the entire West Coast to use treated effluent as its primary water source. Moorhen Marsh is located on the west side of I-680 near the MVSD Administration Building and Treatment Plant and immediately adjacent to the Interpretive Center used by the students participating in the Wetlands Field Trip Program. Download an aerial map of the marsh complex.


McNabney Marsh (formerly known as Shell Marsh) is a 130-acre restored, seasonally tidal wetland located east of I-680. The major area of McNabney Marsh lies southward and eastward of Peyton Slough and is referred to as McNabney Marsh East. The 20 acres comprising McNabney Marsh West lies west of Peyton Slough. McNabney Marsh West, combined with the 20 acres immediately adjacent to and east of the slough, makes up the 40-acre portion of the McNabney Marsh belonging to MVSD.

The remainder of the marsh and adjoining uplands to the east are currently owned by the East Bay Regional Park District. Since 1988, MVSD has managed McNabney Marsh jointly with the East Bay Regional Park District, the Contra Costa County Mosquito and Vector Control District and the California Department of Fish and Game.

The marsh complex is an important stop over along the Pacific Flyway and a number of species use the wetlands as nesting habitat including American Avocet, Black-necked Stilt, Canada Goose, Mallard, Marsh Wren, and Ruddy Duck. Download the MVSD Bird Check list. If you would like to make special arrangements to bring a group of people out for a birding field trip, please contact the District at info@mvsd.org or 228-5635.


Visitors have access to both Marshes Monday – Friday 7:00 am to 5:00 pm excluding holidays. Please check in at the Administration Building before heading out. The observation platform along the plant road in the south end of McNabney Marsh is also open the first Saturday of every month from 7:00 am to 5:00 pm. Download driving directions and map here.


9-30-2010-044Fall 2010: Six interpretive panels were installed throughout Moorhen Marsh by the MVSD Board of Directors. Topics covered in the panels include: the historical significance of Moorhen marsh, mosquito control in wetlands, the Peyton Slough Watershed, and marsh denizens. Come out and take a look!

The tide gates on Peyton Slough in Rhodia Marsh were closed on October 21st. We anticipate the gates being re-opened around May 1, 2011.


Wild Birds Unlimited of Pleasant Hill held a bird walk on Saturday, October 2nd and MVSD held its annual Fall Bird Walk on Saturday, October 23rd. Forty-five species were seen on the October 23rd trip including Belted Kingfisher, Common yellow-throat, American White Pelican, and Green Heron. The highlight of the day was a female Cooper’s Hawk that flew from the direction of I-680 towards McNabney Marsh and struck and killed a Killdeer near the ground in view of the participants on the observation platform. After the hawk caught its breath, it picked up its prey and flew back over the freeway towards Moorhen Marsh. Cooper’s Hawks are not common in wetlands so this was a very unusual sighting!

GB Heron flying CommonYellowthroatWarbler Belted Kingfisher.jpeg


River Otter sightings

otter wideA family of nine river otters has been repeatedly spotted in both Moorhen Marsh (Peyton Slough, Ponds A2, C, D, and E) and McNabney Marsh (Peyton Slough and West Channel) from mid-October through mid-November. Otters have been seen actively fishing, grooming, and walking across levees.


International Bird Rehabilitation Rescue Center (IBRRC) in Suisun City has released 4 species in the marsh complex this fall including: Common Moorhen, Gadwall, Mallard, and Wilson’s Snipe. For more information regarding the IBRRC follow the link.
If you have wildlife sightings to share please contact the District at 228-5635 or info@mvsd.org.