PREVIOUSLY

• Phase One of Elk River’s ‘Ecosystem-Wide Restoration Project’ OK’d, Aims to Address Flooding

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Wetlands that drain into the Elk River are being reworked this summer, the first phase of an extensive restoration effort in the estuary.

A 40-acre area along Swain Slough, just south of Eureka and east of U.S. 101, is this year’s target in a broader effort to restore 857 acres of tidal marshes.

Construction on the Elk River Estuary Restoration Project began July 16. This summer, dikes are being removed and tidal channel networks are being restored.

“For the most part, we are attempting to just reoccupy the former alignment of tidal channel networks in the Elk estuary,” said Katy Gurin, project manager for conservation nonprofit CalTrout.

This, she said, will make a big difference for the creatures that live in the tidal area.

Like roughly 90% of historic tidelands along Humboldt Bay, the original system of waterways was lost. Across the bay, most tidelands were diked and drained for ranching, or as part of other development.

Gurin said habitat there is essential for fish, including coho salmon. These waterways serve as a nursery for young salmon who need to adjust to saltwater after living in the Elk River, the largest tributary to Humboldt Bay.

Restoring these first 40 acres will give more room for fish confined to narrow channels, she said. The edges of tidal channels give space for fish to eat bugs or for sensitive plants to grow.

“So many organisms in the estuary really rely on tidal channel networks, because it’s a good place to feed. It’s also a good place to duck out of high, fast flows,” she said.

The design also includes several ponds that birds will use.

The land was purchased by CalTrout from a rancher, who Gurin said faced failing infrastructure and pasture converting back to tidelands. Funding for land acquisitions in the project comes from the Coastal Conservancy.

It’s part of a managed retreat strategy employed by CalTrout. Willing landowners in areas vulnerable to sea level rise can use funds from land sales to buy agricultural land elsewhere, if they want.

“This is a really important strategy in many areas because there isn’t a real, feasible way to protect these lands from sea level rise,” said Gurin. She said dikes can be raised, but Humboldt Bay is seeing the highest relative rates of sea level rise in the state. Even with higher dikes, groundwater would still inundate the land in certain areas.

Eventually, the property will be transferred to the California Department of Fish and Wildlife and become publicly owned. 

Construction will wrap up this fall, followed by a revegetation phase in the winter and spring (including planting Humboldt Bay Owl’s clover, seeds of which were recently collected).

Many more years of restoration in this estuary are planned, including work on private property. The effort will reduce flooding of agricultural lands, according to CalTrout.

The entire Elk River estuary project area. Map via CalTrout.

“It’s just the first phase of a project that will have many more phases in the future, and is really going to transform the Elk estuary into a place that’s going to be much more abundant and healthy,” said Gurin.

A similar project just west was competed in recent years, undertaken by the city of Eureka. Diked and drained pastureland was restored to tidal habitat. A survey found 21 fish species and three crustacean species in the project area (including endangered and threatened species like the tidewater goby, longfin smelt and coho salmon).

Gurin noted this project, funded by the National Oceanic and Atmospheric Administration, also has an economic benefit to the community. Locals are hired for the work, and it helps an important commercial fish species and supports agriculture through flood control, she said.