Reconnecting prime spawning and rearing habitat for Central Coast steelhead
If April is the cruelest month, October is the least cruel. The summer heat finally breaks, trees explode in color, big orange caddis bounce around and salmon and steelhead are pushing into rivers.
October is also the end of the construction season for many Trout Unlimited restoration projects. Such projects can take years to move from concept through design and planning to construction––which, ironically, may take only a few days.
Exhibit A is TU’s Pickell’s Dam removal on Little Arthur Creek, a tributary to the Pajaro River, an important watershed for South-Central Coastal steelhead on the California coast.
A hurdle to steelhead removed
Pickell’s Dam had long been the biggest impediment to steelhead passage in this stream. At 30 feet high and built more than a century ago, the dam prevented fish passage at all flows to more than three miles of good spawning and rearing habitat. This project, led by TU’s Central Coast steelhead project manager Tim Frahm, was completed in early October and took five years from start to finish, although bulldozers took out all the concrete in a mere six days.
This work removed the dam, its non-functional fish ladder, a concrete slab and restored some 300-feet of stream channel, enabling subsurface water to rise and flow upstream of the dam, in the dry season, for the first time in decades. In addition, concrete removal allowed cobble and gravel, which had been trapped upstream, to mobilize when flows rise after winter storms, improving spawning conditions downstream.
Now that this dam is gone, TU will manage the construction of a pedestrian bridge over the creek on the project site, to enable continued access for the property owner.
Important habitat for steelhead now accessible
Like so many coastal streams south of San Francisco Bay, Little Arthur Creek is relatively short and, during the dry season, small enough to hop over in places. Yet this stream plays an outsized role in sustaining the South-Central Coastal Distinct Population Segment (DPS) of steelhead, which is ESA-listed as threatened.
That’s because Little Arthur Creek is a spring-fed stream whose channel is relatively undisturbed, providing the best remaining habitat for all life phases of native O mykiss in the entire watershed.
It seems improbable that steelhead could reach Little Arthur Creek from the ocean, under any conditions. The mainstem Pajaro River runs through some of the most productive farmland in California and its channel has been highly modified for most of its length. Moreover, water quality and clarity in the Pajaro are sketchy.
Yet in years when winter rains bust open the sandbar at its mouth and connect the Pajaro to the Pacific, steelhead and other anadromous fishes such as Pacific lamprey swim in. And they don’t stop swimming until they reach the relatively clean, cold water found in the headwaters, especially Little Arthur Creek.
This fact was evident when Frahm led an effort to relocate fish that might be in the deep scour pools downstream of the dam, prior to breaking down the dam. This work was undertaken during a heat wave––the air temperature at Frahm’s car was over 116 degrees. But the water in these pools, cradled in bedrock and shaded by sycamores was 59 degrees. That day Frahm and crew netted 8 Pacific lamprey, many 2-feet in length, from these pools––and a dozen healthy steelhead, one 18-20” in length––and relocated them to other parts of the stream with good habitat.
Helping fish and farmers
Due to the importance of Little Arthur Creek for steelhead on the central California coast––it is designated “critical habitat” for this DPS––this stream has been the focus of other TU-led restoration and streamflow enhancement work over the past ten years. These projects have focused in particular on developing off-stream storage solutions to help small landowners secure their water supply while leaving more water instream for fish in the dry season.
The Pickell’s Dam removal project culminates many years of efforts by local fishing organizations to improve conditions for steelhead in Little Arthur Creek. The dam’s fish ladder was built nearly 40 years ago with funding from the Flycasters of San Jose, while more recently the Santa Cruz Fly Fishing Club and the Steinbeck Country Chapter of Trout Unlimited provided funding and volunteer labor for pre- and post-project work to improve habitat conditions at the dam site. Major partners in the Little Arthur’s Dam Removal Project provided key funding and technical support. These partners include the Santa Clara Valley Water District, the California Department of Fish and Wildlife, Resources Legacy Fund, NOAA Fisheries and the Amah Mutsun Tribal Band.