The City and Borough of Juneau is taking a two-pronged approach to combating an abundant — and perhaps invasive — plant in Twin Lakes.
The city is in the process of salting and freezing milfoil, an algae-looking weed that has long compromised the lake’s aesthetic and recreational value. Colby Shibler, CBJ Park Maintenance Supervisor, said Wednesday was the second day crews worked to drain water from the lake to Gastineau Channel during low tide. The extreme tides this week allowed the biggest window for the city to drain the freshwater.
Milfoil near the bank of Twin Lakes on Wednesday, Oct. 30, 2019. The city is looking to knock back the plant by lowering the lake level to allow the plants to freeze, and in the spring, flood the lake with salt water. (Michael Penn | Juneau Empire)
The city plans to keep the water level low over winter to freeze the milfoil stuck on the banks, and then open the gates in the spring to do the salting.
“It seems like it’s getting steadily a little bit worse and a little bit worse, and this last year because we didn’t get to flush it in the spring and the really sunny weather, really made it noticeable,” Shibler said.
The city typically conducts the draining and flushing in the spring because the water in the channel is more saline then versus the fall. But around May, the Alaska Department of Fish and Game stocked the lake with rainbow trout, and both the city and state decided to reschedule the salting.
“We talked about it and said let’s not worry about draining it this year, they’re going to put the rainbows in, everything will be fine,” Shibler said. “And then we had this super sunny summer and that milfoil just took off because of the sunshine.”
“It’s an urban water body that’s very productive,” David Love, ADFG Division of Sport Fish Assistant Area Manager, said.
Love said there’s several possible reasons for the weed’s hyper-productivity, from the amount of light it receives to the influence of fertilizers.
Fish and Game is in the process of determining whether the milfoil is native or invasive, he said. The agency provided a sample and pictures of the vegetation to the Alaska Department of Natural Resources for identification, and he hopes to hear back from the agency in the near future.
Love said the same process will be repeated again in November.
The ramp to a floating dock is shown removed from Twin Lakes on Wednesday, Oct. 30, 2019. The city is looking to knock back the plant by lowering the lake level to allow the plants to freeze, and in the spring, flood the lake with salt water. (Michael Penn | Juneau Empire)
• Contact reporter Nolin Ainsworth at 523-2272 or nainsworth@juneauempire.com.
