watervulnerability

Chugach National Forest Watershed Vulnerability Assessment, Alaska Region (R10)
assessment will stress the course of action that managers can take to mitigate the predicted negative
effects.
Realistically, there are a number of limitations on the analysis, particularly simple hydrologic data. Most
of the Forest is accessible only by aircraft or boat, so data collection has generally been limited to projectspecific
sites on a short-term basis. Since many of the watersheds have little historic or proposed human
disturbance, data collection has not been a priority.
I also assume that given the predicted climate changes for the area, undisturbed watersheds are best left
alone. Predictions for coastal Alaska include increased precipitation, higher temperatures, and more
intense storm events. While there may well be changes in stream flows, flow timing, or other effects,
trying to “correct” those effects without altering other natural processes may be difficult. In addition,
where there are no direct effects to infrastructure or threats to population centers, land managers may
have higher priorities.
Thus, instead of looking at all of the watersheds on the Forest and trying to rank their vulnerability, this
assessment focuses on two of the more highly developed watersheds where more data are available,
where a wider variety of restoration activity might occur, and that are representative of their ecological
areas. These are the Eyak Lake watershed in a coastal rainforest ecosystem near Cordova, and the
Resurrection Creek watershed in a relatively drier boreal forest setting on the Kenai Peninsula.
Figure 1. The Chugach National Forest, its location in Alaska, and the two watersheds that were examined for this
study
Another limitation is that many of the biological effects are intuitively predictable – such as warmer water
temperatures causing salmon eggs to develop and hatch sooner – but how these individual effects interact
with other components of the ecosystem are unknown or cannot be quantified. Thus, there is a vast need
for biological research that can help land managers reach decisions for on-the-ground mitigation
activities.
270 Assessing the Vulnerability of Watersheds to Climate Change