Monitoring to increase for aquatic invasive species in Nevada County
December 3, 2012
"Manifest Destiny" describes the belief held by many 19th century Americans that the fledging nation was fated to expand to the West Coast.
The phrase has taken on a new context in the 21st century as biological scientists have expressed fears that the spread of aquatic invasive species from the East Coast toward the west has the same underlying sense of inevitability.
The principle culprits in the aquatic invasion of North America's waterways are two invasive mollusk species — quagga and zebra mussels — which were introduced into the Great Lakes region via the ballast of freight ships originating in eastern Europe and Ukraine in the 1980s.
The invasion has spread to northern Nevada, causing concern throughout Northern California and coming under the attention of the Nevada County Board of Supervisors at a recent regular meeting.
Since the introduction, the invertebrates have procreated at a rapid rate, which is a reason for their biological success. The thumb-sized mollusks attach to anything, including intake and outtake pipes, drains, cooling systems and boats. The invaders' ability to multiply at an exponential rate kills off native species, alters the chemical makeup of water bodies and can cause hundreds of millions of dollars in damages to water-dependent industries, such as hydroelectric purveyors, power companies and recreational boating outfits.
The population of the mollusks continues to expand in the Great Lakes region, and the species are impossible to eradicate, although pesticides are in development.
The problem was largely contained to the eastern half of the continent until 2007, when the invasive invertebrates were first detected in Lake Mead. Since then, water managers throughout Colorado, Utah, Nevada and California have devised methods to keep the creatures from contaminating other water bodies.
The Tahoe Regional Planning Agency adopted one of the nation's most aggressive boat inspection programs in 2009, which required those wishing to enter the Sierra lake's famously pristine blue waters to have their boats thoroughly checked along with requiring the operators to disclose which water bodies the boats had previously entered.
In 2010, voluntary inspections were implemented at Donner Lake, Boca and Stampede reservoirs and the Nevada County Board of Supervisors recently considered an ordinance that would make inspections mandatory at all of the county's major water bodies.
Indications of quagga mussel were detected in two reservoirs in the northern part of Nevada, including Lahontan and Rye Patch Reservoirs, said Chairman Ted Owens during the November meeting of the supervisors, who supported a comprehensive ordinance for the county.
Many northern Nevada residents also use lakes in eastern Nevada County for recreational purposes during the summer, and the fear is as inspections take hold, they will move west to avoid inspections and fees, Owens said.
Theresa Crimmens, coordinator of the Truckee Regional AIS Prevention Program, said in outreach conversations with boaters in the eastern part of the county, inspectors found more than 80 boats that had previously been in infested waters.
Crimmens said that the inspections are voluntary and that officials have no ability to enforce restrictions on boaters who have navigated infested waters in the recent past.
The supervisors expressed support for the program but did have reservations about the nature and timing of implementation of a comprehensive program.
"It's a good idea to express a policy that expresses that we have a potential threat," said Supervisor Nate Beason. "But I'm a little unclear on how we enforce it and who will pay for it."
The supervisors agreed to approve the ordinance as it applies to county water bodies located on the east side of the Sierra crest and to use the program as a test pilot to determine whether it was right for water bodies on the western side.
"(East side managers) will go through the various operational changes and then at some point we can decide how we're going to do it on the west side," said Supervisor Hank Weston, noting part of the delay for implementation in the western portion of the county has to do with the multiplicity of entities that manages water bodies.
The U.S. Forest Service, Bureau of Land Management, Nevada Irrigation District, California State Parks, U.S. Army Corps of Engineers and other agencies need to be consulted before a comprehensive ordinance is installed on the west side of the county, Weston said.
To contact Staff Writer Matthew Renda, email email@example.com or call (530) 477-4239.