California Dam Removal Revives Historic Salmon Habitat as Spawning Nests Return

In 2024, environmental efforts in California led to the removal of an 18-foot dam from Neefus Gulch, successfully restoring 1,600 feet of stream channel. According to reports from the Times of India Science Desk, this project reopened habitat that endangered Central California Coast coho salmon had been unable to reach for more than seven decades. By January 2026, monitoring surveys recorded eight spawning nests, known as redds, in the newly accessible reaches above the former barrier.

Neefus Gulch serves as a tributary to the North Fork Navarro River located on California's Mendocino Coast. For generations, an earthen dam obstructed the channel, blocking adult salmon and steelhead from swimming upstream to spawn while preventing juvenile fish from accessing cool, shaded pools. The structure functioned as a legacy of prior land use, creating a strict limit on the life cycle of fish relying on connected waterways.

Funded by NOAA and executed by Trout Unlimited in 2024, the dam removal restored 1,600 feet of stream channel and reopened approximately 1.3 miles of habitat for coho and steelhead. This action followed a previous NOAA-supported project that replaced an undersized culvert nearby, completing the necessary framework to restore full passage through the gulch section.

The response from aquatic life materialized quickly. On December 6, 2024, a Trout Unlimited team identified the first juvenile steelhead utilizing habitat above the former dam site. Shortly after, project manager Nicole Herrara spotted a female coho within the restored channel reach on January 6, 2025. Initial surveys counted 17 salmon nests in Neefus Gulch, with four located in the newly opened habitat. By January 2026, monitoring confirmed eight spawning nests in the previously inaccessible reaches.

Biologists note that the Neefus Gulch project operates as part of a broader restoration push along the Mendocino Coast. Over the past two decades, NOAA Fisheries, The Nature Conservancy, Trout Unlimited, and other regional partners have focused on reconnecting streams, eliminating barriers, and restoring floodplains for the endangered Central California Coast coho salmon, designated as a NOAA Species in the Spotlight.

These collective initiatives have coincided with positive population metrics. During the 2024–2025 spawning season, monitoring teams estimated that more than 30,000 adult coho returned to Mendocino Coast rivers. This figure represents a doubling of the previous season's record of 15,000 fish and a significant increase compared to the roughly 3,000 fish returning annually during certain years of the past decade.

Habitat complexity remains vital for coho salmon, which typically spend about 18 months in freshwater before migrating to the ocean and returning as adults to spawn. Historically, healthy redwood forest streams contained abundant woody debris that generated deep pools and slow-water refuges for juveniles. Decades of logging, road building, and channel simplification depleted much of that natural structure, leaving an estimated 5 percent of historic winter habitat available today.

Similar recovery patterns have emerged elsewhere in the region, such as at Dry Dock Gulch on the lower Big River. Following the replacement of perched road culverts with a wider, fish-friendly design, monitoring teams documented 315 juvenile coho utilizing the restored alcove and stream during the 2023–2024 season.

Despite positive indicators, scientists emphasize that strong single seasons do not guarantee full species recovery. Coho remain endangered, facing ongoing environmental challenges from drought, severe winter storms, and changing ocean conditions. Nevertheless, the combination of expanded habitat, careful management, and rising adult returns points to a shifting trajectory for the population.

Future restoration work is already scheduled. Trout Unlimited plans to address barriers at Duffy Gulch within the Noyo River watershed and Cooper Mill Creek in the Eel River sub-basin, while The Nature Conservancy advances floodplain projects on the Ten Mile and Navarro rivers using NOAA funding. Organizers hope these continued efforts will ensure that the recent returns in Neefus Gulch mark the beginning of a wider ecological revival.