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Hetch Hetchy Aquatic Invasive Warning Trailhead Signs
Yosemite National Park » Hetch Hetchy Aquatic Invasive Warning Trailhead Signs » Document List
The purpose of this project is to install "Stop the Spread" warning signs at trailheads leading down to the Tuolumne River below the O'Shaughnessy Dam. These signs are needed to warn people that Didymo, an aquatic invasive algal species, has been documented in the river below the dam. The signs would inform visitors on how to identify the species and how to check and clean their gear to help prevent spreading this invasive to other waters.
The 12 inch by 18 inch signs would be installed at the Poopenaut Trailhead and at the dam on existing sign posts. The vinyl signs would have a Wosky brown background with white text and would exhibit the following content:
WARNING! The invasive algae "Didymo" is present in this river
STOP THE SPREAD! Before moving to other waters:
• CHECK your clothing, shoes, waders, and gear for mud and plant debris, remove material and leave on site.
• CLEAN your clothing and gear with HOT water AND one of the following: dish soap (1 cup detergent per gallon water) OR bleach (1/2 cup bleach per gallon water) OR table salt (1 cup salt per 1 1/4 gallons) DRY completely for at least 48 hours. OR carry "clean" gear for use in other waters.
• AVOID FELT-SOLE WADERS? Consider carbide stud replacement soles, detachable cleats, or sticky rubber.
There will be three photos of Didymo in various stages of bloom for identification Sketches illustrating "Checking" "Cleaning" and "Drying" boots or gear.
The 12 inch by 18 inch signs would be installed at the Poopenaut Trailhead and at the dam on existing sign posts. The vinyl signs would have a Wosky brown background with white text and would exhibit the following content:
WARNING! The invasive algae "Didymo" is present in this river
STOP THE SPREAD! Before moving to other waters:
• CHECK your clothing, shoes, waders, and gear for mud and plant debris, remove material and leave on site.
• CLEAN your clothing and gear with HOT water AND one of the following: dish soap (1 cup detergent per gallon water) OR bleach (1/2 cup bleach per gallon water) OR table salt (1 cup salt per 1 1/4 gallons) DRY completely for at least 48 hours. OR carry "clean" gear for use in other waters.
• AVOID FELT-SOLE WADERS? Consider carbide stud replacement soles, detachable cleats, or sticky rubber.
There will be three photos of Didymo in various stages of bloom for identification Sketches illustrating "Checking" "Cleaning" and "Drying" boots or gear.