Hikers and backpackers are being warned to steer clear of water contact in a small lake within the Rogue-Umpqua Divide Wilderness Area because of a bloom of a potentially toxic form of blue-green algae.
Fish Lake, within the high-elevation wilderness that straddles the Rogue River and Umpqua River watersheds, contains levels of anabaena flos-aquae that are more than four times higher than the state Department of Human Services considers safe.
People who plan to camp at the 90-acre lake are warned against attempting to filter the lake's water because portable filtering systems cannot remove the algae and related toxins. Also, horses and other animals should not drink from the lake, according to the Umpqua National Forest.
Not all blooms create toxic water conditions, which are most common when the algae dies and the toxins are released. Exposure to toxins can produce symptoms such as numbness, tingling and dizziness that can lead to difficulty breathing. Symptoms such as skin irritation, weakness, diarrhea, nausea, cramps and fainting should receive medical attention if they persist or worsen.
No one in Oregon has fallen sick from exposure to the algae, but the World Health Organization said it has caused illnesses and even deaths elsewhere in the world. A dog died last summer after it consumed algae-laced water along the Umpqua River near Elkton.
The state Department of Human Services has adopted the WHO guidelines, which recommend keeping the advisory intact for two weeks after a bloom dies to allow time for the toxins to dissipate.
However, the advisory can be lifted after one week if tests show toxins are below unhealthful thresholds.
Fish Lake can be reached by hiking two trails — Fish Lake Trail and Beaver Swamp Trail — west to east in the Umpqua Forest's Tiller Ranger District, forest spokeswoman Cheryl Caplan says.
From the east side hiking west, the Fish Lake Trail can be accessed off Highway 230, but it is a very long hike into the lake and used primarily by packers, Caplan says.
Two other lakes in the Umpqua Forest, Diamond and Lemolo lakes, also remain under public-health advisories because of potentially toxic algae blooms.
In Jackson County, Willow Lake has been under a public-health advisory for algae since April 21.
New fish ladder on N. Umpqua
The Oregon Department of Fish and Wildlife is building a new fish ladder on the North Umpqua River that will make it easier for wild salmon and steelhead to spawn upstream of the agency's Rock Creek Hatchery.
The $4 million project will create a new fish ladder and sorting station at the hatchery east of Roseburg.
The sorting station will allow hatchery workers to select wild salmon, steelhead, sea-run cutthroat trout and even Pacific lamprey and let them migrate upstream while keeping fin-clipped hatchery fish returning to Rock Creek.
Also, a new fish screen will protect juvenile salmon and steelhead as they migrate downstream past the hatchery.
Work on the facility, which includes an educational facility, will cause the hatchery to be closed to the public through February 2011.
The Joe Merchep Umpqua River Foundation provided design work and raised the money for the project. GRC Contracting of Roseburg will build the facility, which can be used by schools across the county.
Reach reporter Mark Freeman at 541-776-4470, or e-mail firstname.lastname@example.org.