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Weed killer proposed for invasive plant choking West Anchorage lakes

  • Author: Zaz Hollander
  • Updated: September 28, 2016
  • Published June 6, 2015

Sand Lake, a West Anchorage haven for floatplanes and waterfront living, is so choked with a submerged plant called elodea that by midsummer, green ropy tendrils snare boats.

"It actually slows us down," said Marietta Hall, founder of the Alaska Rowing Association, which is based at the lake. "It gets tangled on our skegs and it gets wrapped around our oars. I'm sure plane owners can feel it on their pontoons too."

Given the heavy floatplane traffic there, the state wants to quash the outbreak of the invasive waterweed in Sand Lake and two others before it spreads to other Anchorage or Matanuska-Susitna Borough waters. It's believed a floatplane already carried sprigs from Sand Lake to Alexander Lake, the remote Susitna Valley destination where elodea turned up last year.

Elodea is a leafy plant that is often seen undulating inside aquarium tanks. But the weed can infest lakes and slow-moving streams with dense mats that foul floatplane rudders and hinder boat traffic, choke out native plants, drive down property values and suck up oxygen that salmon and other aquatic life need to survive.

That's why the Alaska Department of Natural Resources wants to apply an herbicide called fluridone to kill elodea in Sand Lake, as well as Little Campbell and DeLong lakes. The U.S. Fish and Wildlife Service is providing $110,000 for the project.

While some on the lake say it's about time somebody poisons the plants, others say the herbicide plans are premature or even risky.

Anchorage arrival

Elodea (it's generally pronounced eh-LOW-dee-yah) can be spread by boats, trailers, floatplanes, aquarium lovers and even school classes using the plant for lessons, officials say. A fragment can start a new bloom.

First spotted in Alaska in the early 1980s in Eyak Lake near Cordova, elodea dropped off the radar until mats showed up in Chena Slough near Fairbanks in 2010. Blooms in the Anchorage lakes and on the Kenai Peninsula were discovered after that. The state says elodea is now found in 19 rivers, lakes and sloughs in Alaska, many around Cordova.

The discovery of elodea in the three Anchorage lakes triggered research and community outreach from the Anchorage Soil and Water Conservation District. Sen. Mia Costello, R-Anchorage, obtained $115,000 over two legislative sessions to look into the problem in the three lakes.

Now agencies hope to start fluridone applications this summer, according to Heather Stewart, DNR's invasive plant coordinator. Three years of application could be necessary, according to a draft environmental assessment out for public review. A public comment period on the state's draft environmental assessment for the elodea eradication closes June 15.

The state hopes to get additional funding to use herbicides in Alexander Lake, Stewart said. It's likely there will be a similar program in Fairbanks but not this year, given all the community stakeholders involved.

A community meeting in Anchorage is planned for 6 p.m. on June 17 in the Sand Lake Elementary School cafeteria.

Stopping the spread

Elodea was first documented in Sand Lake in 2011. Speculation on the cause of the outbreak tends to center on a misguided pet owner.

"Undoubtedly some dipweed dumped a goldfish bowl with elodea in the lake," as longtime resident Don Frantz put it.

Frantz, 74, keeps a red 1949 Aeronca Sedan tied up at his dock on the canal on the southeast end of the lake and said he tries to clear his floatplane's water rudders before taking off.

"But it's all over the lake here, and it's going to be all over the Susitna basin, so they'd better get their act together," he said.

Frantz and some other Sand Lake users say it's about time somebody did something about elodea given all the money spent so far studying the problem with no results. He doubts the state will move ahead, though.

"If they don't do something, it's just going to be a swamp," he said. "You can tell I'm a little frustrated with the whole thing."

Not everyone agrees with the state plans, however.

Former DNR chief v. DNR

Skeptics of the plan include Harold Heinze, a former commissioner of DNR -- the very agency proposing the treatment.

Heinze doesn't live on the lake but knows people who do. He said Friday in an interview that his concerns center on the process the state is using to approve the use of fluridone and the "terribly downplayed" potential human health risks at play.

Heinze, who served as commissioner under former Gov. Walter Hickel, said he doesn't think the state has proved the herbicide is safe for people in and around the lake.

Heinze wants the permit denied until the state takes actions including holding meetings on health risks; documenting rejection of other factors influencing elodea, including stormwater discharge; publicizing the results of Kenai Peninsula eradication efforts; and winning the approval of the Municipality of Anchorage's public health sector.

"There are potentially significant public health issues related to this stuff and it seems to me that that needs to be in the forefront of the process," Heinze said.

There are other critics of the state's plans, including the nonprofit Friends of the Anchorage Coastal Wildlife Refuge, which questions the state's determination that elodea is not native to Alaska waters. Backers include the Cook Inlet Aquaculture Association, a private nonprofit involved in salmon enhancement that wants elodea eradicated to help fish.

The Sand Lake Community Council doesn't have an opinion on the plan, its president said Thursday, because nobody briefed them on it.

'One of the most benign chemicals'

Stewart, the state invasive plants coordinator overseeing the review process, says there is no evidence that the herbicide is dangerous to people and preliminary evidence shows that the Kenai program is working.

The state proposal calls for "very low" levels of fluridone in the lakes averaging 9 parts of herbicide per billion parts of lake water. That's well below the 150 parts per billion allowed by the U.S. Environmental Protection Agency for water used for drinking, according to the state's draft environmental assessment.

Watering with treated lake water, however, could kill garden plants and lawns, the assessment says. Lakeside property owners will be notified by mail and signs will be posted in public-access areas.

"There's no swimming restrictions, there's no drinking water restrictions," Stewart said. "There are some restrictions with water use, garden or lawn use, because it will affect plants."

There are no restrictions for fishing during application, she said. "It is one of the most benign chemicals that you can put in a water system."

Early success on the Kenai

The same chemical is helping wipe out elodea in three Peninsula lakes, according to agencies doing eradication there. In Beck Lake, the most infested lake, elodea occurrence was reduced from 70 percent to zero, according to a flier distributed by the Kenai Peninsula Cooperative Weed Management Area. In Daniels Lake, occurrence was reduced from 22 percent to zero. In Stormy Lake, because of a late initial treatment, elodea is still present but occurrence was reduced from 50 percent to 20 percent.

Two of the three lakes were treated strictly with fluridone last year, Stewart said.

Some critics of the proposal, however, say Sand Lake will be trickier than the Kenai lakes to treat because of the high nutrient loads coming from fertilized yards or a contentious sewer line.

Even Frantz, the lake resident who favors herbicides, said he'll believe it when he sees it.

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