watervulnerability

Chugach National Forest Watershed Vulnerability Assessment, Alaska Region (R10)
Watershed Restoration
Restoring damaged watersheds to improve their natural function is widely seen as the key to increasing
resiliency to the effects of climate change (Furniss et al. 2010, Haufler et al. 2010). The Eyak Lake
watershed has not been severely damaged, but there have been restoration opportunities, and some still
exist.
The CRWP has taken the lead in implementing restoration projects through their FishWatch and Million
Dollar Eyak Lake programs. The Forest Service, ADF&G, Native Village of Eyak, and others have
worked with CRWP to identify and prioritize projects. Some of the specific projects have included the
following.
• Replaced three undersized failing culverts with an arch culvert that restores passage to upstream
fish habitat and downstream transport of spawning gravels to sockeye salmon spawning areas in
the lake.
• Installed a Stormceptor oil and grit separator to remove sediment and hydrocarbons from street
runoff and an urban stream that flow into the lake.
• Removed an artificial spit and abandoned floatplane dock that adversely affected sockeye salmon
spawning habitat in the lake.
• Revegetated disturbed shorelines where roads border the lake. Vegetation will reduce erosion,
trap sediment runoff from the roads, and provide shade and cover to improve fish habitat.
• Worked with the City of Cordova to address snowplowing and dumping practices to help keep
sand, salt, and hydrocarbons from entering the lake.
Thus, many of the existing problems have been addressed. There are still some culverts that prevent fish
passage, but the loss of habitat is relatively small, and replacement costs would be high. The CRWP, in
partnership with Ecotrust, ADFG, the US Fish and Wildlife Service, and the Alaska Department of
Transportation, has also developed a culvert replacement prioritization protocol that has been used in the
Eyak watershed and surrounding areas (CRWP 2011). The highest priority sites are outside of the
watershed.
Eyak Lake Watershed Summary
The Eyak Lake watershed was chosen because it is typical of coastal Alaska and because its climate
change issues would be similar for most rainforest watersheds in southcentral and southeast Alaska.
Higher precipitation, melting glaciers, and more frequent rain-on-snow events increase the possibility of
floods, erosion, increased sediment transport, and changes to channels in depositional areas. All of these
increase the risks to infrastructure and fish habitat.
As discussed by Rothwell and Bidlack (2011) there are many data gaps that hinder the development of a
water budget for Eyak Lake, therefore, it is difficult to quantify flows and their effects. There are also no
models that can predict and quantify snow avalanches and how they affect the landscape. However, a
general look at the issues and values allows land managers to identify possible mitigation actions, or
things to leave as is – in this case the existing flows and habitats that appear to be functioning well.
Maintaining the habitat and the diverse genetic stocks may be all that mangers can do to buffer the effects
of climate change.
This brief study also shows the value of an active, concerned community. NGO’s like the CRWP have
taken an extensive role in identifying and implementing restoration projects. The Prince William Sound
Science Center, Ecotrust, and others are conducting studies that will provide baseline data for future
287 Assessing the Vulnerability of Watersheds to Climate Change