Recent investments in bridges and public parks have brought human beings improved access to the Los Angeles River. The next big project will work on access for the living creates who literally call the river home.
Last week, the state Wildlife Conservation Board approved funding for the design, permitting, and construction of the initial component of a project which will ease the migration of California steelhead trout along a quarter-mile area section of the river just north of Downtown Los Angeles. The project, referred to as Reach 8A over the overall river restoration project, will spans roughly 1,300 feet just south of the Main Street Bridge.
According to an environmental notice posted lasted year by the Department of Fish and Wildlife, the restoration involves the following elements:
- An inset channel will be constructed adjacent to the existing low flow channel. The inset channel will be lined with concreted rock to add roughness and variability to the streambed, with a meandering thalweg to provide diverse hydraulic conditions for fish passage at a range of design flows.
- Anchored boulder clusters will be installed in the existing low flow channel, sufficient for adult southern California steelhead passage during migration windows. These boulders will provide recommended water velocities and migration paths without the need for an inset channel.
- Resting pockets for southern California steelhead will be placed approximately every 100 feet to provide in-channel hydraulic diversity, low velocity zones, and cover that would occur in a natural system. The resting pockets are designed to provide low- velocity refuge where southern California steelhead can rest and recover during migration.
- Vegetated habitat features to allow for vegetation establishment within the channel will be installed, including planter boxes and weepholes/penetrations through the channel lining. The vegetation will enhance cover for multiple species, provide hydraulic diversity and promote biodiversity throughout the Reach 8A Project site.
The project is described in a presentation to the board as the first fish passage within the larger L.A. River watershed, offering a connection to spawning and rearing habitat in the mountain tributary streams. It would also lay the groundwork for future modifications to the concrete-lined river.
Stillwater Sciences is spearheading the project work relating to the fish passage.
The full restoration project, already estimated to cost more than $1 billion when approved a decade ago, would include the Reach 8A segment within an overall 11-mile corridor stretching from the Downtown area up toward Griffith Park. One of the landmark projects undertaken toward that end has been the planned restoration of the Taylor Yard, a former rail storage facility which will be converted into 42 acres of public open space.
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- Los Angeles River (Urbanize LA)