The Redwood Region Audubon Society walk meets every Saturday at 8:30 a.m. where South I Street dead-ends at Klopp Lake. This Saturday, November 7, Bill Rodstrom leads it. The group walks out along water that started the week in Arcata's kitchens and bathrooms. The ponds, the treatment wetlands and the three enhancement wetlands around Klopp Lake are working parts of the City of Arcata's wastewater treatment facility. This fall, for the first time since 2022, the first phase of rebuilding the head of that system is complete.
Four years of work at 600 South G Street
The City of Arcata reported in September that Phase One of the Arcata Wastewater Treatment Facility Improvement Project broke ground in December 2022 and was finalized in June 2026. Construction ran through three bird migrations, and the City says finishing it let staff restart public tours of the plant after a four-year break.
The Mad River Union listed the main upgrades when the City announced a June 10 ribbon cutting at the plant, 600 South G St. The chlorine gas disinfection system was replaced with an ultraviolet system. Electrical systems were upgraded for digital control, underground piping was replaced, and the primary treatment headworks and clarifier were completely renovated. The announcement credited City staff, consultants and Wahlund Construction with more than three years of work.
Walkers on the loop around Klopp Lake never see those changes, because they sit upstream of the trails in the plant the water passes through first.
How the water reaches the birds
The City's tour announcement describes the facility as conventional treatment followed by natural treatment, in this order.
- Conventional treatment at the plant: headworks, clarifiers, digesters and sludge drying beds.
- Oxidation ponds, where natural treatment begins.
- Treatment wetlands.
- Three enhancement wetlands, the marsh ponds birders know by name.
The Phase One work covered the first step. The disinfection change was part of the same project. Everything a Saturday walker sees from the Klopp Lake trailhead sits downstream of those rebuilt pieces, so the upgrade reaches the marsh even though it happened out of sight.
What's out on the water in November
The Friends of the Arcata Marsh bird checklist counts mid-July through November as fall at the marsh. Its seasonal list includes Canada Goose, Mallard, Green-winged Teal, American Coot, Black-crowned Night-Heron and Marsh Wren. Among the shorebirds it lists are Marbled Godwit, Dunlin, Least Sandpiper and Western Sandpiper. The checklist was last updated in 2014. It describes what the season usually brings and makes no promise for any given morning.
What a good November morning can look like is on record. Redwood Region Audubon's December 2025/January 2026 newsletter described an early-November visit to the Arcata Marsh with more than 2,000 Marbled Godwits and a pair of Peregrine Falcons. Godwits come in by the thousand, and falcons hunt shorebirds. Both show up on the same treated ponds at the end of the city's sewer line.
Four Saturdays, four leaders
Redwood Region Audubon's regular Arcata Marsh walks are free and open to the public. Every one meets at the end of South I Street at Klopp Lake. The Society's newsletter puts the walk at 8:30 to 11 a.m. The guided walks page lists a different volunteer leader for each week this month:
| Saturday | Leader | Meeting spot |
|---|---|---|
| November 7 | Bill Rodstrom | End of South I Street, Klopp Lake |
| November 14 | Mark Colwell | End of South I Street, Klopp Lake |
| November 21 | Ken Burton | End of South I Street, Klopp Lake |
| November 28 | Kathryn West | End of South I Street, Klopp Lake |
The page tells walkers to bring binoculars and describes the trails as easy to walk, with views of Humboldt Bay. The November 28 walk falls on Thanksgiving weekend, which makes it an option for visiting family.
The Society runs two more regular walks around the bay, both led by Ralph Bucher, who asks people to sign up by email. One is a two-mile walk at the Humboldt Bay National Wildlife Refuge on second Sundays, which this month is November 8. The other follows the Eureka Waterfront on third Sundays, November 15, on a flat, paved trail the Society describes as wheelchair accessible.
Before or after the walk, the Interpretive Center
The Arcata Marsh Interpretive Center is at 569 South G Street, a short drive from the Klopp Lake trailhead. Its listed hours:
- Monday, 1 to 5 p.m.
- Tuesday through Sunday, 9 a.m. to 5 p.m.
- Closed on major holidays, so call ahead on Thanksgiving
The Center handled registration for the City's plant tours, which ran Thursdays at noon from August 13 through September 24. Groups were capped at 20 people, everyone had to be 13 or older and wear closed-toe shoes, and tours met at the 600 S G St. parking lot. That run is over. The Center's phone number, (707) 826-2359, and email, [email protected], are where to ask whether more tours are planned. The City's construction line from the ribbon-cutting announcement, (707) 825-2128, is the number for questions about the project itself.
The month ends with the highest water of the year
The bay sets the marsh's calendar as much as the migration does. The California Coastal Commission's King Tides Project lists statewide King Tides on November 24 to 26 and December 23 to 25, 2026, and January 21 to 22, 2027. Northern California locations may also see them on December 22, January 20 or January 23. The Commission's tide map has the local times.
The November window falls on the Tuesday through Thursday of Thanksgiving week, just before Kathryn West's November 28 walk. The Commission's site also has tips for viewing and photographing King Tides safely, useful if you're heading to the bay edge at peak water.
The Friends of the Arcata Marsh list a King Tide tour with Elliott Dabill on December 4 at 11 a.m. That is the next date on their calendar after the November walks.
A Saturday that ends on the Plaza
The Audubon walk wraps up at 11 a.m., and the Arcata Plaza Farmers' Market runs every Saturday year-round. In November its hours are 9 a.m. to 2 p.m. They shift to 10 a.m. to 2 p.m. from December through March. That leaves three hours to get from Klopp Lake to the Plaza. For more on how Saturdays work downtown, see our summer guide to the Plaza and the Community Forest and our Arcata neighborhood page.
The agents at Coldwell Banker Cutten Realty live and work around Humboldt Bay, and the marsh is one of the places we're happy to show visiting friends and family. If you're showing someone around Arcata this season and want to talk through which corners of town fit how they spend their weekends, Contact Us Today.
