watervulnerability

Coconino National Forest Watershed Vulnerability Assessment, Southwest Region (R3)
STEP 2 - Assess Exposure
Background
During initial work on this assessment, exposure was included after a generic assessment of water
sensitivity. In the final assessment procedure, exposure was evaluated prior to sensitivity. This allowed
the team to focus on a narrower list of potential hydrologic changes, derived from consideration of how
predicted exposure would affect hydrology, and which of those changes were important to the water
resource values included in the assessment.
Historic Changes
The first step in assessment of exposure of the selected watersheds to potential climate change was to
look at relevant historic climatic data. Review of some available long-term data from Flagstaff shows a
general pattern of warming (Figure 10), with a less-clear pattern relative to precipitation and snowfall
(Figure 11). Regional long term data from the Arizona Water Atlas (Figure 12) indicates a much more
dramatic increase in air temperature since 1960, and a decline in precipitation starting about 1966, except
for a few years of above-average precipitation in the late 1970’s to mid 1980’s.
Figure 10. Average daily air temperatures from Flagstaff, 1950-2006 (Staudenmaier et al. 2007)
141 Assessing the Vulnerability of Watersheds to Climate Change