Baseline Vegetation and Surface Water Monitoring after Restoration Activities at Latgawa Creek

Located in the Cascade Mountains of Jackson County, Oregon, decades of grazing and water diversion practices have impaired ecological function of Latgawa Creek and surrounding wet meadow complexes. Proposed restoration activities are aimed to restore hydrologic function along Latgawa Creek by installing a series of Post Assisted Log Structures (PALS),and treating riparian invasive species. The intent of the PALS is to reverse the channelization within Latgawa Creek and raise the local water table by slowing water flow and encouraging the accretion of sediment behind the structures. This project proposes to monitor landscape changes from these restoration activities and help address a current gap in a rapidly developing field of study. Specifically, we will record data before and after restoration activities including: 1) measures of plant community composition and structure with a focus on noxious weed cover and riparian woody species density and, 2) measures of improved hydrologic function within the stream-meadow complex. Measures of hydrologic function will include in-stream discharge, surface water temperature, and surface water storage capacity in riparian areas impacted by the PALS. Additional project partners include ODFW, independent field biologists, and the Klamath Bird Observatory.

The temperature cooling effects predicted to occur after the installation of PALS will benefit downriver populations of Rogue River Fall Chinook Salmon, and merits monitoring efforts that seeks to quantify the trends and magnitude of cooling effects in order to inform local and basin wide ecological and biological management. Rising instream temperatures have been a devastating problem that negatively impacts salmon populations in the Pacific Northwest, and is addressed explicitly by the Conservation Plan for all Chinook Salmon in the Rogue Species Management Unit. Warming regional temperatures due to climate change are currently compounded by the use of reservoirs to control water levels and induce drawdown into the fall season and the impacts of development along the Rogue River that reduce vegetation shading benefits. The resulting increases in water temperature in the majority of the Rogue River have been identified as one of the leading causes in low juvenile survivorship and declines in adult migration upstream during summer, late summer, and fall spawning seasons (ODFW 2013). The installation of PALS will slow flow, increase soil hydric connection and will support an increased amount of riparian vegetation. The increase ion vegetation is predicted to increase both forb and woody species functional classes, which will inherently include riparian shrubs and trees that will shade surface water. Increased shading in addition to increased pooling and slowed flow will cool instream water temperatures on site. Water cooled on site will of course travel downstream into the broader Rogue River. Latgawa Creek will increase its function as a cooler water input source to the broader riverine system in this way.
The monitoring proposed here will specifically document cooling effects and the altered seasonality of cooler temperatures that can be used by local fisheries practitioners to better understand cool water inputs from headwater systems of the Upper Rogue Management Unity. Vesper Meadow Education Project will share the project findings with restoration practitioners, state and federal entities, tribal partners of the project, and with the public upon request to better serve a coordinated effort to improve habitat for Salmonid species in our region.

References:
Oregon Department of Fish and Wildlife (2013). Conservation Plan for all Chinook Salmon in the Rogue Species Management Unit, https://dfw.state.or.us/fish/CRP/docs/rogue_fall_chinook/Rogue_CHF_Plan_Final_1-11-13.pdf