Mill Creek Dam Removed in Santa Cruz Mountains

Sempervirens Fund completes post-fire dam removal to restore creek and improve Coho salmon habitat, part of long-term restoration of previously logged redwood forest

Los Altos, Calif. — October 4, 2021Sempervirens Fund announced today that they have removed a dam on Mill Creek in the San Vicente watershed.

“For more than a century Mill Creek dam impeded Coho salmon from reaching desperately needed spawning habitat,” said Sara Barth, Sempervirens Fund’s executive director. “Removing the dam has been a missing piece in restoring creek flow and improving sediment conditions critical for spawning. A restored creek is also essential to the health and resilience of the surrounding redwoods and other nearby and downstream habitats at San Vicente.”

The Mill Creek section of the San Vicente watershed is prized for its heavy summer flow of cold water—even in current drought conditions—largely due to a substantial limestone karst system underground. Highly durable granite cobble, trapped behind the dam for a century, can now make its way downstream and into the watershed system, improving miles of potential salmonid spawning habitat, especially for endangered Coho salmon, at the southern end of their range.

Mill Creek Dam
The CEMEX dam once obstructed Mill Creek in San Vicente Redwoods, preventing ideal conditions for endangered Coho salmon habitat.

“Habitat for salmon is scarce and impediments like dams diminish their access to critical waters and the gravelly sediment that makes for ideal spawning grounds,” added Ian Rowbotham, Sempervirens Fund’s Land Stewardship Manager.

San Vicente Redwoods is an 8,852-acre stretch of forest that is currently owned and managed by four conservation organizations: Sempervirens Fund, Peninsula Open Space Trust, Save the Redwoods League, and Land Trust of Santa Cruz County. Near Davenport, it is the largest privately held redwood forest in the Santa Cruz Mountains. The CZU Lightning Complex wildfires in August and September 2020 scorched more than 86,000 acres, including all of San Vicente Redwoods lands. Water lines for Davenport, which ran across the top of the dam, were destroyed. CEMEX funded the re-routing and replacement of their water lines earlier this year and agreed to remove the dam. In late March Sempervirens Fund received a $550,000 grant made through the Open Rivers Fund, a program of Resources Legacy Fund supported by The William and Flora Hewlett Foundation. The grant has been further leveraged by support from individual donors for the ongoing restoration work at San Vicente.

Since 2011, the organizations have partnered to steward the property’s old-growth redwoods and eight creeks, home to many regionally important species of wildlife and plants, including the endangered Coho salmon. While rare in the Santa Cruz Mountains, dams like the one on Mill Creek were built early last century to support redwood logging. Their utility has long since expired, and removal is the best option for repairing the ecosystem. San Vicente’s partners also collaborate with regional conservation teams, such as Resources Conservation District Santa Cruz County, to implement large-scale restoration efforts.

Sempervirens Fund and its partners have also initiated research projects with the Amah Mutsun Land Trust, San Jose State University, and UCLA to monitor and survey fish populations in Mill Creek and in the greater San Vicente watershed, including Coho salmon, steelhead trout, and lamprey eels, including the use of environmental DNA techniques. Past restoration projects along Mill Creek, including the introduction of large woody debris, have already reinvigorated steelhead populations, which have been present this year.

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About Sempervirens Fund

California’s first land trust, Sempervirens Fund protects and permanently preserves redwood (Sequoia sempervirens) forests, wildlife habitat, watersheds, and other important natural and scenic features of the Santa Cruz Mountains, and encourages public appreciation and enjoyment of this environment. sempervirens.org.

About the RCDSCC

The Resource Conservation District of Santa Cruz County facilitates stewardship of private and public lands by connecting people with the technical, financial and educational assistance they need to conserve and manage natural resources. rcdsantacruz.org.

About Peninsula Open Space Trust

POST protects open space on the Peninsula and in the South Bay for the benefit of all. As a private nonprofit land trust, POST has been responsible for saving more than 80,000 acres since its founding in 1977. POST works with private landowners and public agencies to create a network of protected lands so that present and future generations may benefit from the careful balance of rural and urban landscapes that makes our region extraordinary. Visit openspacetrust.org for more information.

About Save the Redwoods League

One of the nation’s longest-running conservation organizations, Save the Redwoods League has been protecting and restoring redwood forests since 1918. The League has connected generations of visitors with the beauty and serenity of the redwood forest. The nonprofit’s 26,000 supporters have enabled the organization to protect more than 216,000 acres of irreplaceable forest in 66 state, national and local parks and reserves. For information, please visit savetheredwoods.org.

About Land Trust of Santa Cruz County

The mission of the Land Trust of Santa Cruz County is to protect, care for, and connect people to the extraordinary lands that make this area special. Information is available at landtrustsantacruz.org.

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