watervulnerability

White River National Forest Watershed Vulnerability Assessment, Rocky Mountain Region (R2)
Figure 5. Possible runoff changes predicted from down-scaled global circulation models for the Colorado River
basin (Christensen and Lettenmaier 2006)
In summary, there are three potential outcomes of the anticipated climate change exposure. Most
importantly, runoff volumes are likely to decrease, potentially exacerbating low flow conditions. This
would likely be accompanied by higher water demand for irrigation, associated with higher air
temperatures. All signs suggest an inevitable conflict between the Aquatic Habitat and Water Uses
resource values.
Secondly, although the published exposure data make little reference to flood events, there appears to be a
trend toward more extreme weather events. The possibility of higher and more frequent flood events
would have a direct impact on the Infrastructure/roads resource value.
Lastly, as noted previously, we have seen average air temperatures increase over the last 30 years, and the
data suggest a continuation of that trend. This would logically translate to increases in stream
temperatures. However, since Colorado River cutthroat are typically pushed to the upper limits of their
range through competition with brook trout, their reproductive success can be limited by cold water
temperatures. In this rare case, an increase in stream temperatures may actually work to their benefit. For
119 Assessing the Vulnerability of Watersheds to Climate Change