Klamath and Trinity River Intra-Gravel Water Temperatures, 2014 and 2015

Temperature recorders were used to monitor water temperatures in spawning gravels (intra-gravel) and in the water column above spawning gravels (surface) in the Klamath and Trinity Rivers from September 2014 to late June 2015. Water temperature recorders were installed in areas having high densities of Chinook Salmon redds to assess potential differences in predicted embryo incubation and subsequent emergence timing calculated using intra-gravel versus surface water temperatures. In general, intra-gravel water temperatures were warmer in the fall and early winter and cooler in the spring than surface water temperatures. Findings of this study are important given the influence of intra-gravel water temperatures within redds on the development of salmonid embryos and the resulting influence on timing of emergence.