The new Petaluma sewage treatment plant, named the Ellis creek Water Recycling Facility (ECWRF), came on line in May 2009 and opened to the public in July 2009. The physical plant occupies part of the 90 up-slope acres of the 270-acre site, along with some seasonal wetlands and 30 acres of polishing wetlands. The polishing wetlands are an arm of the treatment plant which gives a final degree of cleanup to the water by removing more organics plus metals. The remaining 180 down-slope acres of the site consists of uplands and over 100 acres of brackish tidal wetlands which are connected to the Petaluma River at high tides. Some upland acreage is set aside for leased production of hay crops which will also provide cover and food for wildlife.

The ECWRF is designed to support Petaluma’s needs for at least 50 years with a capacity to handle eight-million gallons of sewage per day and provide recycled water as either secondary-treated for agriculture, or tertiary-treated for golf courses and parks. The Petaluma recycled water program will expand over the coming years and help Petaluma conserve incoming potable water. The site was designed to be very environmentally responsible with a LEED – Silver compliance, but was not LEED certified due to the high costs of the certification process. Total construction costs were $ 125 M.

The site is open to the public dawn to dusk, except for the areas where the mechanical processing of the sewage is located and the brackish tidal wetland, which is closed to the public between 15 January and 31 August to protect the nesting, endangered California Clapper Rails. The tidal marsh is easily observed from the Shollenberger Park loop trail to the north. There are over three miles of trails at Ellis Creek, including a connector trail to Shollenberger Park. Much of the area is considered to be a wildlife sanctuary, as requested by the grantors of funds ($4.1 M) used to purchase the site – the California Coastal Conservancy and the Sonoma County Agricultural and Open Space Commission.

Visiting the ECWRF and Wildlife Sanctuary 

ECWRF is entered from the east end of Cypress Drive. A 60-car lot is located just inside the gate as well as a public bathroom, and someday an informational kiosk. The usage rules are the same as for Shollenberger Park. There is also a 0.3 mile trail from the southeast corner of Shollenberger Park which connects to the Ellis Creek trail system. See aerial photo and map below.

Birding/nature hotspots along the three-mile-trail system include the polishing wetlands (year-round) and the seasonal wetlands (winter/spring) located between the bathroom and the polishing wetlands. Birding may be done year-round in the trees lining the edges of the property and also along the Tidal Marsh Trail from 1 September to 14 January;  at other times that trail is closed for Clapper Rail nesting. Docents of the Petaluma Wetlands Alliance offer free public tours at 9:00 AM on the fourth Saturday of the month, unless it is raining.

The Kaiser entry is near A, the Cypress Drive entrance is B. The Shollenberger trail link is C.