SE field researcher Shaw Allen stands below the large, sediment-filled Agua Caliente Debris Dam on this Santa Ynez River tributary.

Only fifty years ago, thousands of adult steelhead trout (Oncorhynchus mykiss) made their annual spawning migration up the Santa Ynez River. In the 1940’s the Santa Ynez River was thought to have the largest run of steelhead south of San Francisco Bay. Prior to the completion of Cachuma Dam (1953), the steelhead run on the Santa Ynez River was estimated to be as high as 25,000 adults (Titus, et al 1994). This estimate was made decades after the completion of Gibraltar Dam (1920), which blocked much of the upper watershed, thus the historic run size prior to any modifications on the river were likely much higher.

Anthropogenic migration barriers on the Santa Ynez River prevent steelhead from accessing a majority of their habitat and has brought the steelhead run close to extinction. The upper Santa Ynez River watershed remains in a relatively natural and protected state within the Los Padres National Forest. High quality habitat also occurs on private land in the lower river and tributaries. Some habitat above complete barriers to steelhead continues to support a naturally reproducing rainbow trout population that still retain ancestral ties to the native steelhead population. This rainbow trout population may be contributing outmigration of individuals to the persistent remnant anadromous steelhead population downstream of Bradbury Dam. Observations of O. mykiss that were made while surveying migration barriers are noted within the report.

Shaw Allen unwinds the measuring tape across the Alder Creek Diversion Dam, which feeds water, and sometimes trout, to Juncal Reservoir on the upper Santa Ynez River.

This report provides information about the location of migration barriers and their impacts on steelhead and rainbow trout movement in the watershed. Upstream natural limits are identified or estimated to identify historic steelhead distribution. Individual barrier assessments within this report provide barrier locations, photographs, descriptions, fish passage diagnosis, and site-specific recommended actions. Large dams, road crossings, grade control structures, flood control channels, and water releases from dams are identified as the main migration barriers and limiting factors to steelhead within the watershed. While improving steelhead migration to available habitat below Bradbury Dam is important to preserving the remaining population, providing additional access upstream of impassable barriers to former spawning and rearing habitat is essential to restoring a wild, self-sustainable steelhead population to the watershed.

Sunset over the Pacific and sandbar at the mouth of the Santa Ynez River.	Excellent trout habitat occurs upstream of the river’s dams within Indian Creek.
Kayaking survey among massive oaks along the mainstem Santa Ynez River.	Winter kayak survey of the Santa Ynez River below Cachuma Dam.
Inaccessible to steelhead because of Bradbury Dam, Santa Cruz Creek contains some of the highest quality trout habitat in the entire watershed.	Aerial view of the Santa Barbara City owned Gibraltar Dam, which was the first major dam built on the Santa Ynez initiating the steelhead population’s decline.
The Mono Debris Dam prevents upstream migration of Santa Ynez River rainbow trout to highly productive habitat upstream.	The construction of the impassable Cachuma Dam (1950-1953) devastated one of the largest steelhead runs south of San Francisco.
A dragonfly casing clings to an alder tree along Indian Creek in the Santa Ynez River watershed.	The natural upstream limit for fish migration in one of the Santa Ynez River’s uppermost tributaries, Juncal Creek.