watervulnerability

Shasta Trinity National Forest Watershed Vulnerability Assessment, Pacific Southwest Region (R5)
Infrastructure
Figure 20 displays results from the assessment of relative risk to infrastructure. Resource value was based
on relative densities of roads and recreation sites in nearstream areas, road crossings and water diversions.
Areas depicted in green are least likely to have infrastructure affected by extreme events. Watersheds
shown in red are expected to have the greatest changes in peak flows and will be most vulnerable to
impacts associated with extreme events. Investing in watershed improvements that buffer runoff response
(disconnecting road crossings, etc.) may be most efficient in watersheds with greater resilience (green).
This model needs more work to better synthesize resource values. Wilderness areas obviously should
have greater resiliency and lower vulnerability; at this point, trail crossings are included in the model and
result in higher vulnerability ratings.
Figure 20. Watershed Vulnerability to Climate Change from Extreme Events
RESPONDING TO CLIMATE CHANGE
In ecology, resilience describes how much disturbance a system can "absorb" without substantially
changing its condition and structure (Bakke 2009). In regard to recovery, habitat restoration, and
conservation of at-risk aquatic species, resiliency also requires that certain key habitat characteristics or
processes will change little, or not at all, in response to climate change (Bakke 2009).
204 Assessing the Vulnerability of Watersheds to Climate Change