LLWA Meeting Minutes - Aug. 31, 2015
Special meeting to discuss chemical treatment of Long Lake
PRESENTERS: Apple Valley City Officials Jessica Schaum and Jane Byron
OVERVIEW: It’s been the goal for several years to improve Long Lake’s water quality and manage the curlyleaf pondweed. Current strategies, including two Long Lake drawdowns, have not produced anticipated results and curlyleaf is still at mostly low to moderate densities according to surveys in the lake each summer. One area had high densities in the 2014 survey. The best strategy may be a combination of tactics that may include future chemical treatments to help reduce curlyleaf.
The purpose of this meeting is to review all options and discuss a chemical option. Chemical treatments alone are not a solution, but part of a toolkit to solve a complex problem. Even if the chemical option receives 100% approval, it’s a lengthy process. Treatment would follow after permits and funding are received and would not happen until May/June of 2016 at the earliest.
DISCUSSION:
Expectations: No lake has completely eradicated curlyleaf pondweed. Best case is to reduce areas of concentration and manage it.
Methods to manage curly leaf (refer to Long Lake Curlyleaf Pondweed slide):
Drawdown
Self harvesting
Mechanical harvesting
Chemical treatment (City)
Chemical treatment (homeowner near shore)
Each has pros, cons, limitations and required permits.
Long Lake differs from other area lakes in several ways.
On many lakes the public owns the water and homeowners own private shore.
On Long Lake about 70% of the lakebed is covered by privately owned lots.
One resident owns a significant portion of the lake itself (roughly 50%).
OVERVIEW OF EACH PROCESS AND THE REQUIREMENTS:
Drawdown - requires homeowner signatures only (75%) and no cost. Two drawdowns completed to date.
Self harvest - homeowners can pull up to a 50’ x 50’ area in front of property with no permit up to 50% limit in entire lake. Protocol for self-harvesting is to remove all invasive weeds and put on shore line to dry out then put in land refuse bin.
Mechanical harvest - boat harvester picks up weeds. May require a boat ramp and $4,000 - $10,000 (up to 50% of lake area and 150’ from shore). City collects bids for harvesting and homeowners pay per property if they opt in for shoreline mechanical harvesting.
Chemical treatment - 150 feet from shore with permission from property owners, $300-$600 per acre up to 5.1 acres, (15% of lake). City survey will identify heaviest concentration areas. Homeowners on shore can opt in to do treatments. If 10 homeowners all wanted shoreline treatment then it becomes discussion point among homeowners to determine what should happen first. City funds the survey, reviewed and approved by DNR.
Self-treatment requires permit ($35). Homeowners must obtain individual permits to do shoreline treatments on up to 15% of lake.
PROCESS FOR CHEMICAL TREATMENT
Need to determine high priority areas in the lake (City survey will determine this). Submit survey and permit request to DNR. DNR then double checks acreage of treatment area request.
Letter sent to every homeowner explaining plan and inviting homeowner to opt in. DNR keeps track of requests/opt-ins to ensure acreage doesn’t exceed maximum.
Alimagnet example: $300/acre for treatment. Alimagnet had density reduction over a decade of harvesting. 2014 was first chemical treatment. Density levels did decline following chemical treatment, but several high density areas still exist.
QUESTIONS:
Will curlyleaf flourish in areas left untreated?
Many factors are involved in chemical treatment success including length and severity of winter. Anecdotal evidence shows that treating 15% of lake helps reduce plant growth beyond the area that is treated.
What’s the process for chemical treatment -- does it kill it or does it reappear?
It does not get rid of curlyleaf permanently. It helps year to year in some communities. With mechanical harvesting we are taking truckloads of material that ultimately turns to phosphorous in time, which is a plus. If one treatment eliminates highest density areas, the DNR could potentially deny future permit requests.
When is next scheduled drawdown?
Fall 2017 is next scheduled drawdown. Every four to five years as city attempts to mimic legacy drought periods. Drawdown level can only go as low as level in Farquar.
Will duckweed become a problem?
Duckweed is unlikely to be an issue even if homeowners see some in the lake. The swiftness of Long Lake water flow to Farquar keeps it moving through.
Does the City view drawdowns as successful?
We did get results in drawdown. We expected more, but it did work.
If we did chemical treatment shouldn’t we do a drawdown the following fall?
This would be an option if homeowners agree to both in the same year.
Has water quality improved at all since drawdowns began?
Water quality has improved in recent years - from worst point with phosphorous, we have cut phosphorous level in half. You won’t always see translation to visible improvement in water year to year. It takes multiple efforts and projects working together to really achieve the goal. The State goal for water is a phosphorous concentration and a few other indicators. If water is cleaner, lake will grow more native plants and habitat.
NEXT STEPS:
1) Determine option to continue drawdowns and harvesting, chemical treatments or combination of all.
2) Need to have response from LLWA by January so process can be approved/permitted by April.
3) City also needs to get drawdown schedule from LLWA.
4) At October meeting we will address questions and move forward with a vote.
