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Steelhead Trout, Once Plentiful in Local Streams, Still Swim the Waters of the Arroyo Seco

A proposed L.A. River project could create a new migration passage for the trout in the Arroyo Seco, and reimagine the river through the local region

Published on Friday, April 23, 2021 | 5:55 am
 

There are steelhead trout in the Arroyo Seco and Tim Brick, managing director of the Arroyo Seco Foundation, along with a local fisherman, say they can prove it.

Brick told a loyal group of foundation members Thursday night in a Zoom event timed to commemorate Earth Day that trout have been caught in the pools of the Arroyo Seco north of Devil’s Gate Dam as recently as last week.

In the early 1900s, fish were plentiful in the waters of the Arroyo Seco, said Brick, recalling the popular story of how one morning, three anglers reported a catch of 240 trout below the site of the ranger station due north of Pasadena.

But with the 1920 construction of the Devil’s Gate Dam and the subsequent channelization of the Arroyo Seco stream—turning it into a concrete trough through Pasadena and Northeast LA—it became practically impossible for the steelhead to make their passage from the San Gabriel mountains out to the Pacific ocean.

Since then the number of trout has dwindled, but not disappeared.

Those trout, however, have experienced difficult conditions since 2009, when the Station Fire burned 160,577 acres of the San Gabriel Mountains above the foothills, from Sunland to Pasadena.

And even before then, the trout faced other calamities, Brick explained Thursday.

“There was a very long drought that extended from 2000 to 2018,” he said. “And again, this year, it’s extremely dry. Some people said that there’s no trout near the Arroyo Seco.”

Belief the trout are gone was reinforced by water projects which naturalists believed had an impact on the spawning areas for local steelhead.

The 2019 Arroyo Seco Canyon Project, according to a City of Pasadena report, was then planned to “repair and replace the City’s water infrastructure facilities in the Upper Arroyo Seco that were damaged by debris flows caused by storms following the 2009 Station Fire.

Headwaters of the Arroyo Seco, a main tributary of the Los Angeles River and spawning destination of steelhead trout, circa 1900. (Courtesy of the Pasadena Museum of History)

“The proposed improvements would allow for increased utilization of the City’s pre-1914 surface water rights from the Arroyo Seco and maximize the beneficial use of this important local water resource,” the City report said.

Locals thought the trout had likely died out. Some officials concurred.

“They sent someone out on one of the driest days of the year in October of 2019, and they looked at the stream, and they couldn’t find any trout,” Brick said. “Well, indeed there are trout there.”

Attorney and avid fisherman Steve Oliva caught and released one of them last week. His giddy and jubilant social media posting electrified fans and supporters of the Arroyo Seco.

Now, a new project hopes to make the catching of trout in the Arroyo routine once again, Brick said.

The Los Angeles River Fish Passage and Habitat Structures Design (LARFPHSD) project, led by the City of Los Angeles, is exploring how to design stream improvements that will provide good habitat and conditions for steelhead trout and other native fish in a 4.8-mile stretch of the LA River near downtown LA, according to the Arroyo Seco foundation website.

The project’s objective is to “enhance native fish habitat linkages and migration corridors to the more natural sections of the river and to the upper tributaries. The proposed construction will involve cutting and modifying the concrete channel that now lines the river to enhance habitat and migration corridors for native fish while maintaining flood management capacity,” said a Council for Watershed Health report.

Map courtesy Stillwater Sciences.

In other words, eventually turn the concrete troughs of the Arroyo Seco Flood Control Channel into a soft-bottom river.

The project is within a 4.8- mile section of the concrete-lined channel of the LA River through Downtown LA, rom the Glendale Narrows soft-bottom reach, past the Arroyo Seco confluence with the LA River, and ending at Washington Boulevard, just 20 miles north of the river’s mouth in Long Beach.

“The proposed design process for the 4.8-mile project reach will evaluate fish-friendly design alternatives for the concrete-lined channel and connections to related restoration opportunities such as Piggyback Yard, the confluence of the Arroyo Seco, and the upstream soft-bottom reach of the LA River,” according to published reports.

“The idea is pretty simple,” said Wendy Katagi, of Stillwater Sciences, consultants to the massive project. “We’re trying to deepen and slow the river velocity during migration periods. This is the migration corridor for steelhead through the city of Los Angeles.”

Katagi continued, “This is a leadership opportunity for all of us, so that we can pull concrete out of the channel and create habitat fish passage in this very urban setting. So that in other portions of both the Arroyo Seco channel and lower LA river, similar types of treatments could occur there.”

The project is a team effort, involving a Who’s Who of American waterways and infrastructure, including the aforementioned City of Los Angeles, Council for Watershed Health, Stillwater Sciences, California Department of Fish and Wildlife, US Fish and Wildlife, Bureau of Reclamation, Los Angeles County, US Army Corps of Engineers, the National Marine Fisheries Service, Friends of the Los Angeles River, and the Arroyo Seco Foundation.

According to the Council for Watershed Health, “the project’s goal is to create steelhead fish passage in the LA River as a migration corridor to the upper tributaries of the LA River Watershed spawning grounds.”

“If effective fish passage design and conditions are implemented, steelhead will be able to migrate … and ultimately complete their life cycle,” noted the project fact sheet.

More information on the project is available at https://www.watershedhealth.org/larw-fish-passage.

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