Las Vegas Sun

November 20, 2017

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Mussels now contained but need monitoring

As water-supply and sewage-treatment agencies tackle an infestation of fast-growing freshwater mussels at Lake Mead, not all the news is bad.

The mussels, which are disdained for gumming up waterworks by attaching themselves to pipe openings, apparently have little effect on the outflow of treated wastewater into lakes.

Ron Zegers, who oversees waterworks for the Southern Nevada Water Authority, said Wednesday the quagga mussels don't appear to have migrated outside Boulder Basin, where they were discovered this month.

They were found on a houseboat in Callville Bay on Tuesday, the farthest north in the lake the animal has been found - so far, he said.

Divers are scheduled to look for evidence of the infestation in the Overton Arm of the lake today, and divers will inspect the Water Authority's two intake structures off Saddle Island on Saturday.

"We're going to have to establish a monitoring program," Zegers said. "It's just going to have to become a way of life."

Zegers is scheduled to discuss the effect of the mussels today at the authority board's regular meeting.

Doug Karafa, program administrator of the Clean Water Coalition, told his board Tuesday that the quagga mussel that has been found in Lake Mead is "the cousin - the nasty cousin" of the zebra mussel that has invaded Midwestern and Eastern freshwater areas, including the Great Lakes, in the last two decades.

Karafa said agencies that put water back into the lake, such as the members of his coalition, have few problems with the mussels compared to agencies that take water from freshwater sources, such as the Water Authority, which supplies nearly all the water needed throughout Clark County.

The Clean Water Coalition is a collection of regional sewage-treatment agencies that plans to build a $750 million pipeline to the bottom of Lake Mead to dispose of treated wastewater. The discovery of quagga mussels, which with their close relative the zebra mussel have caused billions of dollars in damage to water systems, docks, boats and infrastructure elsewhere, has sparked concerns among a number of agencies.

Federal, state and local agencies across the West are concerned that boaters could transport the invasive species to other freshwater locations and it could affect irrigation or potable infrastructure in other areas.

Karafa said the Clean Water Coalition would hire a State University of New York at Buffalo expert on the effect of the mussels to advise the agency on how to handle the mussel, which for now has been found only in Boulder Basin, the southern part of Lake Mead.

Karafa also said at the Clean Water Coalition meeting Tuesday that the mussels could have a couple of positive effects. Although the National Park Service, which runs Lake Mead, and other agencies are concerned that the quagga mussel could profoundly affect the ecology of the lake by removing tiny plants and animals that provide the basis of the food chain, Karafa noted that the filter feeders increase the clarity of water.

He also noted that the mussels are edible, "but they're really tiny."

The U.S. Geological Survey, a federal agency that has studied the animals and their effect around the country, says that quagga or zebra mussels, in addition to being small, may not taste very good. And because they filter water that may be polluted, the federal agency advises against eating them.