‘Bubble curtain’ to help contain invasive plants in Tahoe Keys | SierraSun.com

‘Bubble curtain’ to help contain invasive plants in Tahoe Keys

Tahoe Daily Tribune

An aerial view of the Upper Truckee River marsh lands near Tahoe Keys (left). The conservancy's restoration project would reroute river flow from the existing man-made canal by the Tahoe Keys back into the marsh.

Lake Tahoe continues to be a test site for new technology aimed at controlling aquatic invasive plants.

The latest example is the use of a device called a “bubble curtain” in the Tahoe Keys neighborhood, according to the League to Save Lake Tahoe, which is working with the Tahoe Keys Property Owners Association to combat invasive plants that have overrun the channels in the keys.

The bubble curtain, which was installed on May 12, creates a barrier of bubbles in the water column across the west channel between the Tahoe Keys lagoons and Lake Tahoe, according to the League. The device has been used in other locations around the world to prevent debris from moving through an area, but this is the first time the technology has been used to prevent the spread of aquatic invasive plants. It also is the first time it’s been used at Lake Tahoe.

“An infestation the size of the one in the Tahoe Keys is not going to be solved overnight,” Jesse Patterson, the deputy director for the League, said in a press release. “What’s exciting about this technology is that it offers a possible way to contain the threat to Lake Tahoe while we work on the long-term solution for the infestation within the keys lagoons.”

The aquatic invasive plants — primarily curlyleaf pondweed and Eurasian watermilfoil — have been found in warm, shallow waters around Lake Tahoe, infesting more than 90 percent of the Tahoe Keys 172-acre lagoons. The Tahoe Keys Property Owners Association (TKPOA) has implemented numerous programs from skimming floating fragments on the surface to a boat backup station to dislodge fragments from boat propellers and water intakes, reducing their potential spread.

A length of perforated tubing snakes along the bottom of the east channel, fed by an air compressor on the shore to push bubbles in a sheet to the surface. Scuba divers installed the bubble curtain in a “V” formation to drive submerged plant fragments to the water’s surface, and then to the edges of the channel to ease collection and removal. An additional benefit of the bubble curtain technology is that it will trap the stray fragments without impeding boating activity.

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TKPOA also has purchased two Sea Bins — autonomous devices designed in Australia to collect debris in the water — that will be placed on either end of the bubble curtain to capture and remove fragments as they are corralled, according to the League.

“If this pilot proves to be effective, this will be a solution we can turn to for other infested marinas around the Lake,” Patterson said.

The League has provided $6,500 in seed funding for this project and for equipment and software to monitor the infestation.

“This represents one of the most significant efforts in recent years to control the spread of invasive plants in Lake Tahoe,” Andy Kopania, chair of the Tahoe Keys Water Quality Committee, said in the release. “This is a real milestone in our ongoing efforts to control our weed infestation and protect Lake Tahoe.”

The bubble curtain is far from the only cutting-edge technology deployed at Lake Tahoe.

Last summer a pilot project using ultraviolet light was launched in the Lakeside Marina in South Lake Tahoe near the state line. As the Tribune previously reported, the program involved using a specially-made boat fitted with a drop-down panel of UVC lights to combat invasive plants. Research showed that UVC light damaged the DNA and cellular structure of the plants, causing them to die.

More traditional tactics, such as bottom barriers, continue to be used in the Tahoe Keys and elsewhere around Tahoe.

Earlier this month, officials announced a new agreement between the U.S. Army Corps of Engineers and Tahoe Regional Planning Agency that will bring $1 million in federal funding to the fight against invasive species at Lake Tahoe.