watervulnerability

Ouachita National Forest Watershed Vulnerability Assessment, Southern Region (R8)
current condition and a condition with road maintenance and the forest floor closed to OHV use. All
subwatersheds show improvement. Some subwatersheds show enough improvement to move to a lower
risk category. The dark green subwatershed would actually move from a high risk to a low risk and five
other subwatersheds would move from a high risk to a moderate risk. Eleven subwatersheds would move
from moderate to low risk (light green).
Current Condition and B1
The B1 scenario for 2050 found that an
additional four subwatersheds would move
from a moderate risk to a high risk (shown in
dark red) and that one subwatershed would
move from a low risk to a moderate risk
(shown in red). Comparing the current
condition for 2080 B1 scenario provided the
same results. There was no change for the B1
scenario between the near term and long
term predictions.
Current Condition and A1B
The current condition and A1B predicts a
poorer condition than B1. There are 16
subwatersheds that moved from a moderate
risk to a high risk for aquatic biota. In
addition, 15 subwatersheds moved from a
low risk to a moderate risk. The long term
climate change prediction (2080) is worse
with an additional subwatershed moving
from a low risk to a moderate risk.
CONCLUSIONS
The predicted climate changes from TNC
climate wizard and their application to
WEPP is a useful tool to predict different
climate scenarios. The use of Phillips (1993)
was not as useful because of the scale the
data is represented at and improvements in
climate predictions from the early 1990s.
The current Forest watershed condition has 88 watersheds with a high risk and 46 with a moderate risk.
The simple act of maintaining of roads, bringing them up to plan standards, and limiting recreation use
can reduce the number of subwatersheds with high risk by six. The number of subwatershed with a
moderate risk would decrease by 11. Seventeen subwatersheds (almost 10 percent of all subwatersheds)
would move from a higher risk category to a lower risk category by complying with the forest plan (road
and trail standards) and providing maintenance. Over time, all of the various scenarios suggest an
increased risk to aquatic biota. There are many approaches to managing that risk, the least of which is to
provide maintenance.
233 Assessing the Vulnerability of Watersheds to Climate Change