watervulnerability

Umatilla National Forest Watershed Vulnerability Assessment, Pacific Northwest Region (R6)
Stressors or factors that may exacerbate climate change
• Mines: coded 1= mine(s) shows no evidence of impacting water quality; 2= mine(s) has the
potential to impact water quality; 3= mine(s) is actively impacting water quality.
• Ditches, reservoirs: present/absent
• Fire: percent acres burned last 10 years coded 0=0% watershed burned; 1=50% burned in the last 10 years.
• Developments and floodplain roads: Campgrounds and developments coded 0=none,\; 1=1,\; 2>1.
Roads coded 0=0 miles; 1=1-10 miles; 2=>10-20 miles; 3=>20 miles (also under Values).
Overall sensitivity scoring was the simple sum of weighted factors for watershed condition, resiliency,
and stressors, binned into 5 classes per HU12: from 1=LOW Sensitivity (High resiliency) to 5=HIGH
Sensitivity (Low resiliency)
We used a categorical matrix approach to combining and categorizing water resource value and
sensitivity into “Risk-Value” groups.
Exposure
A growing body of published research in the Pacific Northwest shows regional trends in historic
temperatures (warming), precipitation, declining snowpack, and streamflow (Mote 2003; Knowles et al.
2006; Hamlet and Lettenmaier 2007). Exposure represents the pressure or change imposed by future
climate systems outside the historic range of variability. We used University of Washington-based
Climate Impacts Group (CIG)
downscaled gridded data at the
watershed scale for spatial Forest
overlay and identification of
locations of greatest projected
future change. The subwatershed
scale was considered too fine to
apply macro-scale climatehydrologic
model outputs (grid
cells about 6 km 2 Historic compared to 2030
). Changes in
winter and summer temperatures
range from about 3 to 5 °C
increase but spatial differences are
very small (