Mill Creek Dam

Calling back the salmon

About the Project

Mill Creek, nestled in the coastal redwoods north of Santa Cruz, provides salmon with critical cool water flows in the summer months as it joins San Vicente Creek and then meets the ocean. These favorable conditions spurred state and federal agencies to identify the San Vicente Creek watershed as a high priority for coho salmon recovery in the Santa Cruz Mountains.

The 8,500-acre San Vicente Redwoods Preserve is co-owned by Sempervirens Fund and Peninsula Open Space Trust. The 2020 CZU Lightning Complex burned the entire Preserve, melting a municipal water line owned by Cemex, Inc. that ran along the top of a defunct dam on Mill Creek and increasing concerns with the dam’s structural integrity that also impeded fish passage in the watershed. In the fall of 2021, the 12-foot-tall, 25-foot-wide concrete dam, which was built more than 100 years ago to service past mining and logging activities, was removed. Removal released gravel and sediment that was trapped behind the dam and is essential for salmon spawning habitat. Upstream of the removed dam sits a slightly larger dam, built in the mid-1900s. Planning and assessment have concluded that the dam will remain in place because it serves as a backup water source for Davenport, which is difficult to replace.

The region surrounding the dams holds cultural significance to the descendants of the Mutsun and Awaswas speaking peoples who have lived in the region for generations. The Amah Mutsun Land Trust, a nonprofit Tribal land trust created by the Amah Mutsun Tribal Band, has partnered on the project by conducting cultural resource surveys, removing invasive species, and planting native species through its Native American Stewardship Corps. In November 2021, Tribal members resurrected an annual “Welcome Back the Salmon” ceremony that they have not had the reason to hold for many years.

FACTS AT A GLANCE
Owner: Sempervirens Fund and Peninsula Open Space Trust
Size: 12 feet high and 25 feet wide
Project Cost: $775,500
ORF Investment: Feasibility study, dam removal (permitting, design, project management, dam deconstruction), communications, cultural resources survey, research and outreach, Calling Back the Salmon Tribal ceremony
Miles Opened: .25 miles
Fish: Central California Coast coho salmon and steelhead
Status: Removed 2021


RESOURCES
OUTCOMES
  • Restore .25 miles of ideal cold water habitat for Central California Coast coho salmon and steelhead
  • Renew the cultural ceremony, “Calling Back the Salmon,” by the Mutsun and Awaswas speaking peoples
  • Improve spawning habitat by releasing coarse substrate trapped behind the lower dam
  • Reduce risk of uncontrolled breach of the lower diversion dam, located upstream from Davenport
  • Revegetate the project area with native plant species
Hold control key + scroll to zoom

Project Partners

Sempervirens Fund

Peninsula Open Space Trust

Save the Redwoods League

Amah Mutsun Land Trust

California Department of Fish and Wildlife

State Coastal Conservancy

Resources Conservation District of Santa Cruz County

Cemex, Inc.

Waterways Consulting, Inc.