watervulnerability

White River National Forest Watershed Vulnerability Assessment, Rocky Mountain Region (R2)
Figure 3. Possible changes in annual precipitation predicted from down-scaled global circulation models for the
Colorado River basin (Christensen and Lettenmaier 2006)
Regarding precipitation, of particular interest is the change in snowpack with elevation. Figure 4 shows
results from Christensen and Lettenmaier (2006), which suggest that snowpacks are expected to decline at
elevations below about 8,500 feet. In western Colorado, the current transition from a rain-snow
dominated precipitation regime to a snow-dominated regime occurs at around 7,500 feet elevation. This
transition elevation is expected to rise with time and emissions. For this analysis, we considered the
elevation band from 7,500 to 8,500 feet elevation to include snowpack at risk. That is, we expect more of
the precipitation to occur as rainfall, as opposed to snow, which would affect both the timing and
magnitude of streamflow.
117 Assessing the Vulnerability of Watersheds to Climate Change