watervulnerability

Grand Mesa, Uncompahgre and Gunnison National Forest Watershed Vulnerability Assessment, Rocky
Mountain Region (R2)
3. Stream miles inundated by reservoirs, expressed as a percentage of perennial and intermittent
stream network in a watershed inundated by reservoirs greater than 50 acres in size, because at
that scale entire stream reaches or major wetland complexes would be impacted.
Route Related
1. Motorized route (roads and trails) density, expressed as miles of route per sq mi. of watershed.
(Note: Travel management decisions made since 2005 are not reflected in these results.)
2. Motorized route density within buffered riparian area, expressed as miles of routes within the
area of riparian habitat and a 100-foot buffer around riparian habitat by watershed.
3. Motorized route crossing density, expressed as number of crossing (determined by intersecting
roads and trails layers with stream layer) compared to the total stream network (perennial and
intermittent streams).
Past vegetative treatments, expressed as a percentage of the watershed treated by some vegetation
management within the past 50 years.
High frequency of streamside recreational use, expressed as a percentage of the total miles of stream
network in a watershed that have high levels of recreational use (camping, fishing, roads and trails,
developed sites).
Private land inholdings, expressed as a percentage of the total watershed area, was used as a measure of
urban influences based on the assumption that as the amount of inholdings increases there is a greater
potential for developments activities to be located on those private lands as opposed to surrounding NFS
lands.
Abandoned mine land site density, expressed as number of adits and tailings piles by area of each
watershed.
Values for each of the individual factors listed above were calculated and standardized for each factor (as
described above for the values). The overall activity stressors ranking was determined by adding the
individual factor standardized ratings together for each subwatershed. The resulting Activity Stressors
Rankings were classified into quartiles. The top 25% were classified 3 (high), middle 50% were classified
2 (moderate), and lowest 25% were classified 1 (low). Figure 23 shows the resulting Activity Stressors
Ranking.
96 Assessing the Vulnerability of Watersheds to Climate Change