Estuary News

June 2019

Wildlife and Way of Life in the North Delta?

Californians ask a lot of the Sacramento-San Joaquin River Delta, where the state’s longest rivers meet and deliver snowmelt from the mountains. Water suppliers want to reconfigure the Delta’s plumbing via the ever-contentious Water Fix project, which Governor Gavin Newsom just sent back to the drawing board. State wildlife officials want to boost restoration in the region, and the 2019 Delta Conservation Framework outlines their latest plan. And people in the Delta want to live and farm there as they have for generations.

There may not be a way to give everyone what they want from the Delta. But there are ways to restore ecosystems while preserving local communities. This is true even along State Route 160, which traverses the most populated and most intensively farmed part of the region. The highway follows the Sacramento River into the Delta, twisting and turning around leveed islands between Freeport and Rio Vista.

Clarksburg area of North Delta.
Clarksburg area of North Delta. Photo: Amber

This is the North Delta and it’s a spectacular drive. The river beckons as farms ― vineyards, pear orchards, cornfields ― and charming towns roll by. Take a side road, however, and you’ll find there’s even more here to appreciate. The North Delta is vital for birds migrating up and down the Pacific Flyway as well as for Central Valley salmon migrating to and from the ocean.

While most North Delta land is privately owned, some is protected. The Stone Lakes National Wildlife Refuge, nestled on the eastern edge of the region, has grown to about 6,500 acres since its creation 25 years ago. Now the focus is on restoration.

“Historically, the forests that grew along our waterways were up to a mile wide,” says Beatrix Treiterer, the refuge’s assistant manager. “They’re hugely important for migrating songbirds.” Riparian woodlands provide nest sites and food for ash-throated flycatchers, blue grosbeaks, and other songbirds that summer here and winter south of the U.S.

Stone Lakes refuge.
Stone Lakes refuge. Photo: Carson Jeffres

Before restoration, the land was farmed for field crops like alfalfa and tomatoes. “They used as much of the land as possible,” Treiterer recalls. “They didn’t leave much edge habitat.” In partnership with the Sacramento Tree Foundation, the refuge has reforested more than 80 acres along waterways in the last decade. Volunteers planted nearly 10,000 trees including Valley oaks, Fremont cottonwoods, and box elder maples, as well as understory plants.

The benefits to birds were swift. “Even when the trees were small, we immediately saw birds,” Treiterer says. “Before there were hardly any.” Some of the first trees that were planted are now 30 feet high, forming a leafy canopy over a dense understory of native grasses and shrubs like wild rose and elderberry. Today more than 120 bird species use the refuge, which is part of a wildlife corridor system that links riparian habitats in the Central Valley.

Yellow-rumped warbler, a common riparian bird.
Yellow-rumped warbler, a common riparian bird. Photo: Rick Lewis

Wildlife-friendly farms near the refuge also play a key role in conserving sandhill cranes, which winter in the Central Valley. “Farmers are hugely important to cranes,” Treiterer says. “We can’t supply all their energy needs.” The refuge provides roosting habitat while farmers provide foraging habitat, explains Russell van Loben Sels, whose family has farmed the Delta since 1876 and who has farmed the land himself for half a century.

He grows minimum-till corn on about 70 acres right by the refuge, a practice that leaves about five percent of the kernels after harvest. “The kernels are all on top, sandhill cranes love it,” he says. “All they have to do is hop across the levee and into the field.” Before the refuge was established, he only saw a few cranes in his field; now he sees around 100.

Much as van Loben Sels enjoys the cranes, he points out that farming practices must make economic sense. “Farmers are governed by one hard rule of thumb,” he says. “You’ve got to produce or you won’t be farming long.” Many North Delta farmers have converted from corn and other row crops where sandhill cranes forage to high-value crops like wine grapes.

Even so, van Loben Sels believes “there will always be some row crops” due to the Delta’s terrain. Permanent crops do best on the island edges, where the elevation is relatively high. In contrast, row crops are suited to the island middles, where the elevation is lower and the groundwater is higher. 

The interests of North Delta residents and conservationists can also align in other ways. Elk Slough, a winding nine-mile waterway between Clarksburg and Courtland, was once connected to the Sacramento River at both ends. This gave salmon and green sturgeon an alternate migration route through the Delta. Today the slough is leveed at the top, blocking fish that go up it, and open at the bottom, potentially causing floods during big storms.

Partners in a plan to remove the levee at the top and put gates at both ends include affected reclamation districts, which are responsible for flood control. The gates would be open most of the time to allow fish passage, and closed as needed to control floods.

Conservation opportunity region in the North Delta from the 2019 Delta Conservation Framework
Conservation opportunity region in the North Delta from the 2019 Delta Conservation Framework. Map courtesy CDFW

Unlike most waterways in the Delta, Elk Slough has a remnant of mature riparian forest. Tall trees shade the water, keeping it cool enough for salmon. In addition, woody debris from the forest helps fish in several ways: it slows water down so they can rest; offers places where they can hide from predators; and decomposes into organic material, ultimately boosting their food supply. “It’s great habitat,” says Doug Brown, an environmental consultant on the project. “You don’t need to do much for fish except provide access.”

The potential for outside conservation planning to disrupt flood control is a major concern for local farmers and landowners. “The system has adapted and developed over generations in a way that works,” says Erik Vink, director of the Delta Protection Commission. “Anything that changes that could have an adverse impact.”

Town of Walnut Grove
Town of Walnut Grove, where the Delta’s rural way of life is nested in the landscape. Photo: Amber Manfree

He favors focusing restoration efforts on public land, and following the Good Neighbor Checklist developed by the California Department of Water Resource’s Agricultural Land Stewardship Workgroup. Checklist guidelines include involving all neighboring landowners in project planning, and protecting landowners from endangered species-related liability.

Outside planning efforts can also overwhelm Delta residents. “You could go to meetings about plans all day long,” says Anna Swenson, a graduate of the Delta Protection Commission’s Delta Leadership Program and co-leader of North Delta Cares. “It’s like a full-time job.”

Swenson would like to see official local representation in conservation planning for the Delta. “Each island has an elected governing board for the reclamation district,” she says. “I think they should have more of a voice on restoration projects.”

“Everybody has a different idea of what they want us to be,” Swenson continues. “I want us to be what we already are.”

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Sandhill crane. Photo Rick Lewis

About the author

Robin Meadows is an independent science journalist in the San Francisco Bay Area. She covers water and climate change adaptation for Estuary News, is the water reporter for the Bay Area Monitor, and contributes to Bay Nature, Frontiers in Ecology and the Environment, PLOS Research News and Water Deeply. Robin also enjoys hiking and photography.