River Temperature Trends within the Snake Tribal Community
The Snake River, situated in eastern Washington, plays a vital role in the migration and spawning of several species of salmon, including those significant to the Nez Perce tribal lands. A graph in Figure 1, sourced from the USGS in 2023, shows the average August water temperature at a site along the Snake River from 1960 to 2022, revealing a concerning trend of warming. Between 1960 and 2022, the water temperature at the site has increased by 2.2°F.
Salmon are sensitive to water temperature at many stages of their lives, and warmer water can make them more susceptible to disease. Warming river and stream temperatures in the Pacific Northwest will threaten ecosystems and species, including salmon populations.
The Columbia Basin Research's monitoring tools indicate detailed historical and seasonal water temperature data showing an upward trend in summer river temperatures since at least the mid-1990s. These elevated temperatures correlate with increased mortality and migration challenges for salmon populations, especially juvenile and adult Chinook and sockeye salmon.
For salmon on or near Nez Perce tribal lands, the warming waters can disrupt migration timing and reduce juvenile survival rates. For example, the sockeye salmon returning to Idaho's Sawtooth Basin, which historically faced near-extinction, now show a fragile recovery with annual returns varying widely but still influenced by summer heat and low water levels in the Snake River during migration months.
Climate change exacerbates these conditions by increasing the frequency and severity of summer heatwaves and lowering river flows due to altered precipitation and snowmelt patterns. This makes maintaining cooler river sections, like those managed by Dworshak Dam operations, crucial to supporting salmon survival during critical summer months.
The EPA's StoryMap provides information on community connections to climate-related changes, offering a comprehensive understanding of the impact on local ecosystems and species. Technical documentation related to the information is available for download.
In summary, the historical rise in late summer water temperatures in the Snake River due to climate change threatens salmon populations by causing thermal stress that impacts migration and survival. This is particularly important for salmon runs that pass through or originate from the Nez Perce tribal lands, where water quality and temperature directly affect their cultural and ecological significance. Efforts like habitat conservation, dam management, and climate adaptation are key to mitigating these impacts.
- The elevated average August water temperature in the Snake River, combined with climate change, could potentially lead to increased incidents of medical-conditions in salmon populations due to their sensitivity to water temperature.
- The ongoing climate change, with its increasing frequency and severity of summer heatwaves, might worsen the warming trend observed in the Snake River, negatively affecting the health-and-wellness of various species inhabiting the river's ecosystem.
- Evidence from environmental-science indicates that climate change could exacerbate environmental conditions, such as soil and land degradation, that in turn affect the salmon populations and their habitats.
- Scientific monitoring tools, like those used by the Columbia Basin Research, suggest that climate change might contribute to neurological disorders in salmon populations by causing higher temperatures and oxygen depletion in the water, stressing their sensitive central nervous systems.
- Advancements in medical-conditions research and health-and-wellness studies could hold the key to understanding the long-term effects of these environmental changes on salmon populations, providing insights into potential solutions for ensuring their survival in the face of climate change.
