Middle Fork John Day Temperature Monitoring

The CTWSRO has implemented numerous restoration projects within the Middle Fork John Day River Intensively Monitored Watershed (MFIMW) alongside multiple partnering agencies. Current monitoring strategies have not detected changes in stream temperatures at the basin wide scale post-restoration. The 10-year and 15-year MFIMW Monitoring Report identified elevated stream temperature as the primary freshwater limiting factor to salmonid productivity. The report also identified a lack of spatially relevant stream temperature data to quantify the impacts of restoration on stream temperatures. CTWSRO plans to target this knowledge gap by increasing and diversifying monitoring efforts beginning in 2025 to better detect impacts of restoration on restored stream reaches. To accomplish this, temperature arrays and hyporheic flow monitoring devices will be purchased and then installed within restored and unrestored stream reaches, which will allow for comparisons of temperatures between these sites. These efforts would require increased funding to support equipment design, creation, and deployment. The nature of the MFIMW is that it is a collaborative effort of many partnering organizations including CTWSRO as well as the Oregon Department of Fish and Wildlife, CRITFC, the North Fork John Day Watershed Council, and the US Forest Service; therefore, this work is supported broadly by partnering agencies also invested in stream temperature monitoring. PCSRF funds will be used to purchase the hyporheic flow and temperature monitoring equipment.





Worksite #1: Middle Fork John Day River - Bridge Creek to Beaver Creek

We plan to deploy a comprehensive array of temperature and hyporheic flux sensors to capture diel temperature changes at both the scale of individual morphologic features (e.g., pools, riffles, and channel margins) and across entire reaches. Specifically, we will install 37 hyporheic flux sensors at strategic locations along the streambed to quantify the direction, magnitude, and temperature of post-restoration hyporheic fluxes. These will be confirmed by periodic discharge surveys throughout the summer that evaluate seepage gains and losses over the extent of each restoration reach. Additionally, we will use 31 Paco stakes (short two sensor flux stakes) to continuously monitor diel water temperatures and shallow hyporheic fluxes around features of interest in the main channel, incoming tributaries where hyporheic influx is present, as well as immediately upstream and downstream of thermally stratified pools. Select stratified pools will be continuously monitored using 10 vertical temperature arrays to determine the magnitude, duration, and rate of thermal change in the stratification dynamics. This suite of measurements will be deployed to complement the existing temperature sensors along the river and tributaries maintained by the MFIMW Water Temperature Monitoring Subgroup and provided by the NFJDWC. Further, a series of existing ground water monitoring stations and 21 new piezometers in the floodplain will provide groundwater temperature and elevations. PCSRF Funding will be used to purchase the equipment, which includes paying the University of Idaho to construct the specialized equipment. OWEB and Oregon Conservation and Recreation Funds will be used to fund two graduate students to install, maintain and analyze the data. Specifically, OWEB funds will be used to fund one graduate student in 3 of the 5 years required to install, maintain the equipment and analyze the data. OCRF will be used to fund a second graduate student in 2 of 2 years required to install and maintain the equipment as well as analyze the data.

Stream temperatures in the Middle Fork John Day River are increasingly limiting the habitat availability, survival, and persistence of native salmonid populations. Restoration efforts have been underway since 2011 to increase habitat area, but there has been no comprehensive assessment of the specific thermal impacts resulting from different restoration strategies. Given the physiological stress that elevated water temperatures place on native fish, particularly in meadow systems like those in the MFJDR, there is an urgent need to identify which restoration actions most effectively enhance water temperature heterogeneity and thermal buffering capacity in order to limit thermal stress on native aquatic species.



This project will provide valuable insights into the thermal improvement potential of restoration actions by utilizing advanced temperature and hyporheic measurement techniques to mechanistically compare the impacts of various restoration strategies across multiple reaches of the MFJDR. This information is needed to advise adaptive management strategies, optimize future restoration projects, and ensure that investments in habitat restoration lead to measurable improvements in salmonid resilience to thermal stress.