Upper Big Springs and Pond Outlet Restoration Project

In 2018, the Lemhi Regional Land Trust (LRLT) received funding from both PCSRF and Bonneville Power Administration (BPA) for design and engineering plans for the Upper Big Springs and Pond Outlet Restoration Project on the Leadore Land Partners (LLP) Conservation Easement (CE). The 80% design was completed in spring 2020. Big Springs Creek is entirely contained on the Leadore Land Partners CE, which closed in 2015, and is held by LRLT. This project was intended to improve habitat for Endangered Species Act (ESA) listed spring Chinook Salmon and summer steelhead. LRLT proposed to construct a habitat rehabilitation project on approximately 3,400 feet of Big Springs Creek and to replace an upstream pond outlet. Big Springs Creek is a tributary of the Lemhi River and is a spring fed channel collecting groundwater and minor surface water. The project area is lacking riparian habitat and is over-straightened and over-widened. The project area has been heavily impacted by historic land use practices which have reduced channel complexity, floodplain connection, and riparian vegetation resulting in degraded habitat for anadromous fish. The Upper Big Springs and Pond Outlet completed plans and permits and was ready for installation, but the landowner became very difficult to contact, and therefore did not give final approval for the project to begin in fall 2021. The project was bid in September 2021, awarded in early October, and the contractor selected. However, the project could not move forward in spring 2022, again due to lack of landowner participation. PCSRF funds that were awarded for installation were therefore returned.

The upper section of Big Springs Creek is lacking riparian habitat, is over-straightened, and over-widened. The project area has been heavily impacted by historic land use practices which have reduced channel complexity, floodplain connection, and riparian vegetation

resulting in degraded habitat for anadromous fish. Overall project goals were to improve habitat for limiting life stages of ESA-listed fish, restore natural channel processes to maintain diverse habitat, and to address shade targets set in the LLP Conservation Easement.

The overall project aimed to maximize short-term and long-term riparian and shade conditions, reduce the channel width to a more appropriate geometry, increase in-stream hydraulic diversity and velocity gradients, increase pool size and frequency, increase interstitial space along margins, and increase in-stream cover. The current pond outlet that drains warm water from the top of the pond was to be moved to a bottom-release outlet, letting cool water into Big Springs Creek.