Lake Benton

[lawdog]

This story is in the Pipestone Star this week. Thought it was interesting:

Lake Benton attacks curly leaf problem

Chuck Draper

Herbicide was applied Monday morning in Lake Benton in an initial attack on Curly Leaf pondweed.

The weed has virturally taken over the shallow prairie lake in recent years and has disrupted summer recreation and greatly reduced water quality.

The lake was treated with the herbicide floridone (Sonar). A coalition of groups hopes that treating the lake early will kill the weed and not affect native grass species that have not yet germinated. This initial application will be followed with another later this spring.

Showers and the threat of thunderstorms did not deter a crew from Michigan Monday morning. With three boats, they had the treatment complete by noon. DNR biologists were on hand to observe the process and will monitor conditions.

The low-level dosage was expected to spread throughout the lake within 24 hours. After that day-long process, usage of the lake can return to normal, which at this time of the year is minimal anyway. It’s stressed that with low dosage of the chemical fish, livestock and wildlife will not be affected. Because desirable native species have not yet begun growing, they should not be affected.

Curly Leaf is an invasive non-native species with a life cycle different from native lake life. It is already growing this April, perhaps already up to two feet tall. It grows early and forms a heavy mat in the lake. It later decomposes and near ruins the water quality. Extreme infestation, such as in Lake Benton, smothers native plants and fish.

Robert Olson, EPA officer for Lincoln County, said the chemical has been tested and used at different levels in many states, although not so much in Minnesota. It has been used in instances against Eurasian Milfoil, a more publicized weed affecting Minnesota lakes.

Still, Curly Leaf affects about 600 lakes in the state. Lake Benton is a trial for the state in that results here will help determine if and how it is used elsewhere.

Olson said the technique is to apply the chemical about 10 days after the ice is off. The water is still cold. (Lake Benton’s water temperature last week was just 48 degrees.) Desirable native plants haven’t germinated yet, but Curly Leaf is already well on its way, is already 1 1/2 to 2 feet high. The goal is to hit it at this stage, kill it, and allow other plants to grow.

This first application used 75 gallons of chemical. “We’re using the lowest amount of chemical that will still be effective. It’s a minute concentration - only four parts per billion in the lake.”

That low concentration is why livestock and waterfowl won’t be affected. Olson said other pollutants in the lake are probably worse that the herbicide. People should stay off the lake for 24 hours after treatment; then normal usage resumes.

The second treatment will use only about half the dosage of the first. That treatment time depends on various factors, but should be completed by early June. The process involves three or four boats criss-crossing the lake with the chemical. Normal wind and wave action diffuse the chemical throughout the lake.

Not a quick fix

Everyone would like to see the lake treated a couple of times and then be fine, but that won’t happen. “In reality, we will have to look at two to three years of treatment,” Olson says. “After treatment we will need ongoing management for a long time.”

That management will include careful monitoring. Treatment might get rid of much of the weed, but leave areas of infestation. They will be “spot sprayed.” The biggest hurdle for enthusiasts of the lake is financing. While only 75 gallons of chemical doesn’t sound like a lot, it costs $1,600 per gallon. The actual application is about $12,500. This year’s treatments will cost of about $125,000. Take that time three for three years treatment.

Olson says residents will get a report on progress in mid-summer at the lake association annual meeting. If the process shows success, there may be a bond issue proposed with proceeds used to finance future treatment.

The association has raised about $20,000 and DNR has contributed $10,000 thus far. There have been other contributions. Last week Lincoln County commissioners approved a loan which will make up the difference. That loan is at three percent interest for three years and could be repaid through tax revenues, through a bond issue.

There are no grant dollars at this point, but Sen. Jim Vickerman told the Star this week that lottery proceeds earmarked for environmental projects may be available in the next grant go-round. A foreign visitor

Curly Leaf Pondweed comes from Eurasia. It’s now found at various levels in a wide range of the United States. In some portions of the world it’s seen as a food source for birds and what Americans consider rough fish.

Just how it got into Lake Benton is not proved. The normal method is through transportation on boats. It’s noted though that other lakes in the area do not have the problem, although it is common for local fisherman to go from lake to lake. Olson said Dead Coon Lake doesn’t have the problem, which seems peculiar in that Lake Benton drains into Dead Coon.

Some say it was evident in the lake by the mid-1970s. An early study identified Lake Benton as being devoid of aquatic life. Some locals have speculated the weed may have been intentionally introduced to solve the problem but no proof has been offered.

[Rost]

I am sure some have mixed feelings about this one. Myself, I believe somthing had to be done. The last time I was on the lake was three summers ago and the weeds were absolutely horrible.

[Austin]

I would just have to say i am glad something is happening. (Contact US Regarding This Word) fine lake right up until the weeds take over. Hope something changes. Hey Corey you do any fishing around Madison? Stuefen said he saw you last week, should of had him ask you then.

Later

Austin

[Rost]

Austin-

Yeah, I do almost all of my fishing here in SD. And so far, it has been amazing. In fact, I have not bought a MN license in 2 years. I do kinda miss the lakes back home though..

[lawdog]

I think you are right Rost, something HAD to be done. I'm not sure it will be good for the fishing (although some say it will be), but that place wasn't too many years away from being unboatable, unfishable and basically unuseable.

[Austin]

Well good news so far. The treatment is starting to work, there are weeds washing up on shore. Now just have to see if it has had any affect on the fishing, less than 2 weeks left.

Austin