A sign in the Tahoe Keys asks boaters to stop and reverse their motors to dislodge weeds on props. Photo/Kathryn Reed

By Kathryn Reed

Tahoe Keys has set up a high-tech boat wash of sorts in order to prevent more invasive weeds from reaching the heart of Lake Tahoe.

Beginning next week the bubble curtain is expected to be fully operational. This device complements the boat backup station that was implemented two years ago. Sea bins will be added later in the summer as a way to more instantaneously pick up the fragments. Those components are on back order.

Together the goal is to keep the Eurasian milfoil and curlyleaf pondweed in the canals. More than 90 percent of the Tahoe Keys’ 172-acre lagoons are riddled with these invasive species. The Keys is blamed for being the source location for the weeds that have turned up in Lake Tahoe proper. That is why the goal is to stop the spread where it starts.

Skimmers will be used to pick up the fragments the boats discard and then they’ll be removed from the waterway.

Greg Hoover with the TKPOA has his hands full with myriad AIS issues. Photo/Kathryn Reed

New this year are larger signs so boaters will be able to better read what they are supposed to do.

The goal is to have boaters stop, then reverse the direction of the prop. That action loosens and in large part dislodges the weeds that have taken hold.

The drawback to this is that as a homeowners association employees cannot mandate boaters do the backup maneuver. They are working on that. Staff, however, is out there at different busy times talking to people about why it is a good idea to do this and are educating people about aquatic invasive species. They have literature to hand to people to drill home the message.

Once boaters do the prop shimmy they will drive through the bubbles near the mouth of the channel.

“The bubbles should strip off all the weeds that are still attached,” Greg Hoover who manages aquatic invasive species for the Tahoe Keys Homeowners Association told Lake Tahoe News. “We will create a monitoring plan to see how successful we are.”

The bubbles are also expected to create a barrier to prevent weeds from reaching the lake. Boats are the No. 1 way AIS spread from one location to another.

This is the first time the bubbles have been used at Lake Tahoe. At their lowest output the pressure is about 0.5 cubic feet per minute. These types of devices have been used to deflect gas and oil spills from sensitive areas.

The harvester is like a lawn mower on water. Photo/Kathryn Reed

Regulatory agencies have studied the potential effect on fish and don’t believe it will be a concern.

TKPOA was just waiting on the final sign off from the city to be able to operate the electricity for the bubbles on a 24/7 basis. The apparatus cost about $30,000, with homeowners footing the bulk of the bill and the League to Save Lake Tahoe coming up with about one-sixth.

To create the backup station with signs and designating clear routes for boaters was another $12,000.

Once the sea bins are installed it will be the first time anywhere in the world that they will be used with the bubbles. They will go in three locations acting as a suction that will trap the weed fragments. Then they will be manually drained.

All of this is on the west channel of the South Lake Tahoe neighborhood. The property owners association has control of this area, whereas the marina owners are responsible for the bulk of the waterway near the boat launch.

While all of these devices are designed to keep the weeds in the lagoons, they do nothing to actually get rid of the plants not attached to a moving vessel. The use of herbicide is still very much on the table. It is in the hands of the Lahontan Regional Water Quality Control Board and Tahoe Regional Planning Agency.

Until a decision is made there is still the harvester that essentially mows the weeds.