Lower Lemhi Reference Reach - Phase 2

The Lower Lemhi Reference Reach Project - Phase 2 is located on the Lemhi River, about three miles upstream of Salmon, Idaho, and covers approximately 0.76 miles of habitat. This project builds on Phase 1, which focused on stabilizing the riverbank along an outer meander bend through the use of habitat structures and revegetation. During Phase 1, the bypass channel used for construction was intentionally left open and converted into a side channel, but over time the river has shifted into this channel, leaving the original meander bend dewatered. Phase 2 aims to reactivate the outer meander bend while stabilizing the headcut at the bypass channel. Additional efforts will focus on creating and reconnecting side channels, constructing islands, developing inset floodplains, building large wood structures, and planting native vegetation.



The improvements will enhance habitat complexity and expand floodplain and side channel habitats, providing critical juvenile rearing and overwintering areas and retaining fish in the Lemhi River for longer periods before they migrate downstream. Trout Unlimited is the project sponsor, working in partnership with the U.S. Bureau of Reclamation for engineering and technical assistance and the Idaho Governors Office of Species Conservation.



Other engineered Structures in metrics refer to engineered riffles.

The main goal of this project is to develop more normative river and floodplain functions to enhance habitat diversity, increasing the capacity of the project reach to support juvenile life stages of Chinook salmon and steelhead. Enhancing and expanding side channel habitat

while increasing habitat complexity in the main channel will provide critical rearing and overwintering habitat that the Lemhi River currently lacks. Constructed riffles will increase floodplain connectivity and pool, riffle, run and glide habitat units. The projects location near the confluence of the Lemhi and Salmon Rivers provides an opportunity provide habitat to all juvenile fish coming from the productive spawning grounds upstream on the Lemhi and Hayden Creek and allow them to grow larger in the Lemhi system before migrating downstream.