The Upper Mainstem Salmon River from the Pahsimeroi River confluence to the headwaters contains Spring/Summer Chinook and Steelhead Salmon returning to the Salmon River basin and Upper Mainstem Salmon. This reach has been identified in NOAA Fisheries Proposed ESA Recovery Plan as having the following limiting factors for listed fish: excess sediment, passage barriers, summer flows, high water temperatures, instream complexity, floodplain function, and entrainment.  Habitat/recovery needs for these species includes removing passage barriers, increasing flows, reducing sedimentation, and preventing entrainment in irrigation ditches.  

Garden Creek, a tributary to the Upper Mainstem Salmon River, is an area of restoration focus in this contract. According to the NOAA Fisheries Spring/Summer Chinook and Steelhead Recovery Plan (2017), tributary drainages with intrinsic potential to support spawning, based on relative habitat suitability under historical unimpaired conditions, include Garden Creek. Garden Creek is a tributary of the Salmon River in the 12 Mile reach near Challis. The confluence of Garden Creek and the Salmon River creates the Hannah Slough. The Hannah Slough and adjacent springs have been monitored by Idaho Department of Fish and Game and have some of the highest densities of Chinook parr in the Upper Salmon.

A passage barrier on Garden Creek at Chipmunk Hill will be replaced in this contract in July/August 2019. The design work for this project was completed in the previous contract (contract 76599 WE S). Design work for additional passage barrier replacement will be done under this contract for implementation in subsequent contracts (in 2020 or 2021).

For many years the Garden Creek system has not been fully connected to the Salmon River due to at least two complete passage barriers and by low flows.  Consequently, many of the culverts/road crossings were installed to meet the lower flows from Garden Creek, particularly on the mid to lower reaches. Garden Creek irrigation management has improved in the last five years which, by way of water administration, has begun to increase flows in Garden Creek. Improvements coordinated by the Custer SWCD began on Garden Creek with a barrier removal and passage reconnection on lower Garden Creek in 2004 funded by BPA. Several additional years of planning and funding has been invested recently in Garden Creek, resulting in increased flows and removal of three major barriers in Garden Creek. Several road and farm culverts have been impacted by increased flows and extreme high water in the spring of 2017 and again in 2018.  As a result, these culverts (sized for the lower flows) have been shown to be partial barriers. Sediment loads due to undersized culverts have also been an impact to the fisheries in the Garden Creek channel. Although some road improvements have been made to widen the road, the county road culvert is narrow and has not been replaced. The banks above the culvert continue to “slough off” and cave, adding sediment to the stream.  One additional farm culvert is proposed for removal in cooperation with a project proposed by the Corps of Engineers and Custer county and would include fencing and stream re-habilitation. This is proposed as a future project.  

Key habitat limitations in the Garden Creek watershed include migration barriers/blockages, temperatures, and streambed sedimentation. This project addresses several limiting factors by reducing sedimentation caused by the narrow road culverts and removes two partial passage barriers which addresses improved connectivity.  The Upper Salmon Basin Tech Team, made up of representatives from multiple agencies, ranks projects based on priorities within the Screening and Habitat Improvement Prioritization for the Upper Salmon Subbasin (SHIPUSS). The two bridge projects were ranked for improved access to spawning/incubation and rearing habitat for Steelhead Trout, Bull Trout, Westslope Cuttthroat Trout, and Red-band Trout. The Custer SWCD works with cooperative and willing landowners to implement projects; in small tributaries such as Garden Creek, these types of projects help build trust and relationships with landowners that may result in future projects in the drainage.

Work completed on Garden Creek since 2004 include:
• Garden Creek Flume installed in 2004 – Reconnect Garden Creek to the Salmon River by fluming the canal over Garden Creek instead of capturing Garden Creek in the Gini Canal. Contract #1994-017-00
• City of Challis – 3rd Street Bridge – Completed by the City of Challis to address a fish barrier.
• City of Challis Water Conservation project and Diversion improvement (PCSRF and Project #2007-268-00 BPA Contract 49514 - 2015)
• Irrigation Consolidation near City of Challis – Reduced three diversions/passage barriers into one fish passable diversion. (Project #2007-268-00 BPA Contract 59926 - 2015)
• Garden Creek Siphon – Lower Garden Creek: removed a seasonal fish barrier and improved flows. (Project #2007-268-00 BPA Contract 72367 - 2016)

The Custer SWCD is collaborating on the Garden Creek project with multiple agencies,  including but not limited to Idaho Department of Fish and Game, U. S. Bureau of Reclamation, Idaho Department of Water Resources, Natural Resources Conservation Service, Trout Unlimited, Office of Species Conservation, The Corps of Engineers, Custer County, and private individuals to address these culverts and improve limiting factors of flow, sediment, temperatures, and barriers on Garden Creek. The Upper Salmon Basin Watershed office and the Office of Species Conservation identified the Garden Creek culvert as an opportunity and assisted in the ranking process along with the Upper Salmon Basin Watershed project.

Other work in this contract addresses monitoring previously installed projects (including fencing and irrigation improvement projects) to extend the life of the projects.  There are approximately eight miles of fencing in the Upper Salmon Basin near Stanley that have been installed in previous contracts and may require repair. Most of the fence in need of repair is jack post and pole fence or log worm fence. An additional 8 miles of fencing and numerous irrigation improvement projects have been installed in the East Fork Salmon basin. Water users are required to maintain the irrigation improvements under contracts with the District; however, extreme high water in 2017 and 2018 has severely damaged some of these improvement structures.  Within this SOW the District proposes having staff revisit and monitor fencing and irrigation improvement projects installed by the Custer SWCD to assess repair needs and ensure long-term viability of the structures.

Planning needs by District staff are addressed within this contract to prepare for out-year projects.  Engineering work will be done under this contract to develop plans for two bridges (to be implemented in future contracts):  one on Road Creek and one on Lower Garden Creek. These have been identified in planning meetings with the Upper Salmon Watershed office sub-committees and technical team members as important fish recovery projects. Planning and engineering will also be done in coordination with NRCS for projects on private land.

The final work element is weed control on the Stark property, which is an 60-acre easement funded by BPA. Custer SWCD would work with Custer County weed supervisor or a private licensed contractor to complete the work.