Warm Springs River and Beaver Creek Large Wood Placement Project II

The Warm Springs River and Beaver Creek Large Wood Placement Project will create critical habitat for resident and anadromous salmonids by utilizing a helicopter to place large woody debris (LWD) structures in strategic locations along a section of the Warms Springs River and a section of middle Beaver Creek. Both are critical locations for salmonid production, as they support all life stages of ESA-listed mid-Columbia River summer steelhead, spring Chinook salmon, and resident redband trout, as well as Pacific Lamprey and bull trout.



These actions will directly address the limiting factors to fish listed above by accomplishing two objectives:

1. Restoring channel complexity and creating critical habitat (e.g., spawning gravels, thermal and hydraulic refugia, overhead shelter, side channel habitat, and deep pools) for salmonid reproduction and survival.

2. Increasing sediment sorting within the active channel to reduce levels of fine sediment in spawning gravels. LWD structures will focus stream energy to scour the streambed and increase sediment sorting.



The Project fits into the 20-year Aquatic Strategy for the Warm Springs Reservation (CTWSRO 2019) co-developed by the Tribes and the environmental consulting firm, Tetra Tech. A key component of the aquatic strategy is the Project Prioritization Matrix developed by Tetra Tech (Tetra Tech and CTWSRO 2018), which is used to identify and rank habitat improvement projects based on a range of environmental and biological metrics. The Matrix was used to identify the need for and general locations of the Project. A design was then completed by Tetra Tech which used analysis of channel morphology and flow-event modelling to further guide the placement of LWD structures. Stream habitat survey and annual redd count data collected by the Warm Springs Fisheries Department were also used when determining LWD placement locations.



This Phase (II) of the project continues the work of Phase I of the project, which was initiated during 2020. Funding from this 2021 PCSRF proposal will be combined with the funding from the 2020 PCSRF proposal to complete the project. Work to occur is detailed below by worksite.



* Note: Because work will occur in two projects (20-Warm-03 and 21-Warm-02), proposed metrics are apportioned Combined metrics from these two projects equal those described below.

Worksite #1: Warm Springs River – LWD structures will be installed along a 2.70 mile reach of the Warm Springs River (37.1 RM – 34.4 RM). As depicted in the 100% design plans, approximately 115 LWD structures in different configurations will be installed. Depending on the configuration, LWD structures will range between 3 and 8 logs each, and the structure configuration used at a specific location will depend on the conditions present at that location and the intended purpose of that structure. A total of approximately 408 logs will be installed in the Warm Springs River reach.



Worksite #2: Beaver Creek – LWD structures will be installed along a 4.60 mile reach of Beaver Creek (8.3 RM – 12.9 RM). As depicted in the 100% design plans, approximately 81 LWD structures in different configurations will be installed. Depending on the configuration, LWD structures will range between 3 and 8 logs each, and the structure configuration used at a specific location will depend on the conditions present at that location and the intended purpose of that structure. A total of approximately 573 logs will be installed in the Beaver Creek reach.



Project effectiveness will be gauged using a before-after-control-impact (BACI) monitoring design at both worksites.

The proposed large woody debris (LWD) additions will provide ESA-listed and culturally significant salmonid species with critical spawning, rearing, and adult holding habitat. LWD has shown to be vital for generating habitat complexity, providing thermal and hydraulic refugia, pool creation, the accumulation and sorting of suitable spawning gravels, and providing protection from predators. Previous fisheries surveys conducted in the Warm Springs River (2006 – 2010) found that juvenile Chinook salmon and steelhead/redband trout utilized LWD structures with respective average densities of 4.2 and 1.1 individuals per square meter (fish/m2) of LWD habitat. Additionally, snorkel surveys conducted in 2017 and 2018 in a reach of the Warm Springs River that was treated with LWD placements in 2016, found the average abundance of Chinook salmon to be between 7 (2017) and 2.8 (2018) times greater compared to a reference, untreated reach. Thus, the proposed LWD treatments are expected to increase the productivity and viability of populations of ESA-listed and culturally significant salmonid species in the Warm Springs River and Beaver Creek.