Newsletter: Issue 39
Message from the Board
Wishing you a happy holiday season! And hoping 2021 will be a year of positives.
A bright spot for 2020 is the continued successful work by the BMLA and continued good health of BML. As this editor has tried to say in the past, the status of AIS in BML would be a disaster without the dedication and tenacity of our organization’s President, Mike Blehert. Since Mike and I started the current BMLA in 2009, his relentless goal has been to stop AIS growth, my task has been to inform and grow membership. We are succeeding. Even though 2020 was a discouraging year in many ways, at least we can take comfort in the fact that our beautiful lake remains as healthy and navigable as ever and that BMLA itself remains strong.
Eurasian Water Milfoil (EWM)
The following summary contains a lot of detail, listed to illustrate that a great deal of work and thought has been involved. The control and eradication of AIS is not a simple matter. The science behind it continues to evolve.
The BMLA in consultation with PLM (our licensed herbicide applicator) tested a new herbicide mix on nine spots totaling about 0.5 acres in BML on July 3 and August 18, 2020. This mix of Diquat, a contact herbicide which quickly kills the Eurasian Water Milfoil (EWM) fronds, and DMA4, a systemic herbicide which can kill the plant roots worked extremely well based on our early September and Oct 5 surveys. We’ll have confirmation of these results next spring since it’s possible that some of the EWM will recover over the winter. A benefit is that this mix is 1/4 the cost of Renovate OTF used in past years and is easier to apply.
In 2019 PLM treated EWM in BML with the new herbicide, Procellacor. This herbicide has a dwell time of only 3 to 6 hours compared to 20 to 24 hours for others we have used so PLM agreed to treat much smaller areas than in previous years. This lower dwell time significantly reduces dilution due to water movement so it is much more effective. Downsides are that Procellacor costs about $2400 per acre and it can only be applied by a trained applicator with specialized equipment. This means the BMLA cannot spot treat with Procellacor.
PLM has experimented with a Procellacor/Diquat mix to reduce cost and (maybe) increase effectiveness.
It is planned that PLM will spot treat EWM in BML in 2021 with Procellacor or a herbicide mix(es). This would be very labor intensive and would require extra mapping and surveying. The treatment would be more effective than BMLA spot treating and would have advantages.
It is feasible that total EWM in BML could be reduced to less than an acre.
When the work done is performed by professionals, it helps insure that EWM and potentially other AIS can be kept to a minimum without intensive volunteer work. The BMLA spot treating team has been and is up to the job. However, spot treating by PLM helps guarantee that treatment of all BLM EWM will continue forever.
The plan for EWM for 2021 is:
PLM will request a permit from the DNR that will allow whole lake treatment (same as past years), but with the ability to add and change as needed with changes sent to the DNR after treatment.
The BMLA and Steve McComas (Blue Water Science) would survey the entire lake as in the past and provide a permit map for large areas to be treated and for patches which would/could be spot treated.
PLM will treat the large EWM areas (4 locations .2 to 1.0 acres totaling about 3 acres) starting about mid- June. The current estimate for spot treating is 20 to 30 areas ranging in size from 10 to 500 square feet.
Two types of equipment will be used on PLM boats: Underwater nozzles or nozzle bars which can be raised or lowered depending on water depth in large EWM growth areas; and two handheld wands for spot treatment.
PLM will repeat treatment at least twice during summer 2021. Labor cost for spot treating will be $200 to $500. The cost of the herbicide mix will be $600 to $1000/acre compared to $2400/acre for Procellacor. The BMLA spent $2900 on spot treating herbicide in 2020 and $5900 in 2019. PLM was also paid $8937 for treatment of 3.76 acres of EWM in 2020.
We received a 2020 cost share grant from the watershed district (CMSCWD). Going forward the CMSCWD plans to emphasize more AIS support.
Watercraft AIS Inspections
Matt Downing of the Washington Conservation District (WCD) reports that the goals for inspections at BML were met and exceeded. Zebra mussels (ZM) were found twice in BML boat inspections. Four other boats had ZM at lakes in the WCD area - White Bear, Bald Eagle, and Clear (2). Two boats were cleaned (only dead ZM). Four were sent to decontamination centers and reports were sent to the DNR for enforcement.
With the commitment of the CMSCWD and lake associations in the county combined with county and state efforts, an additional 850 hours of inspections were performed in 2020 that otherwise would not have been done. In CMSCWD alone, 9,561 inspections were performed. This was 4,527 more inspections than in 2019. As in previous years, emphasis was placed on Square and Big Marine Lakes, with 6,971 inspections occurring on Big Marine. Through the inspection process, boaters were educated on how to better protect the lakes they are using, and steps were taken in every inspection to ensure that invasive species were not present at the time of launch and exit. The BMLA website includes a 2020 inspections summary prepared for Washington County by Matt Downing.
Special thanks to Ken Larson, Vet’s Camp Manager, who shows his love of the lake by being sure that all visiting watercraft at the VC are inspected. In no way will the Vet’s Camp 100% inspection be achieved at the other three BML launch sites. However, the BMLA Board has approved for 2021 a contribution of $7500 (to be matched by CMSCWD) to WCD for additional BML inspections beyond the basic WCD schedule. In 2020, the BMLA and CMSCWD each put $2500 into added inspections.
Wake Issues
The Minnesota Lakes and Rivers Advocates (Minnesotalakesandrivers.org) has commented in their newsletters about possible negative effects of wakes created by wake boats. MAISRC (maisrc.umn.edu) has also looked into the subject. Also, the Star Tribune published several articles on wake issues in 2020. If you are interested, check out these sources. Submit any comments to bigmarinelakeassociation@gmail.com.
