Dear Friends of the Lake,
This has not been a good summer for the lake when you consider weeds floating to shore, water clarity and algae blooms. We have done some checking and want to share with you what we have discovered. The information will be presented in three segments:
1. Curly Leaf Pondweed which is an invasive species and can be a problem in late June/early July.
2. Late July/August weeds floating to shore.
3. Algae blooms and poor water clarity.
Curly Leaf Pondweed (CLP)
In Forest Lake Curly Leaf Pondweed (CLP) is the most common weed . It is also an invasive species. This means if left uncontrolled it will spread and dominate other native weed species of which there are 23 in Forest Lake.
CLP grows extremely fast to form a dense mat like structure at the surface which blocks light and chokes out other native aquatic weed species. The dense weed structure also interferes with recreational use of that area by swimmers, water skiers , tubing, personal watercraft and even sail boating. In late June/early July CLP dies and floats to shore clogging shorelines. As it decays, it releases phosphorus which with warm water temperatures stimulates algae blooms and reduces water clarity.
A top priority for the FLLA is to control and reduce CLP in Forest Lake. Working with the city, the DNR and the Watershed District, 155 acres of CLP weed beds were treated in early May before aggressive growth started. 63 acres were treated on Lake 3, 37 acres on Lake 2, and 55 acres on Lake 1. The weed beds treated were “dominant CLP” which means they were 75% plus CLP. Thus, tons of CLP were eliminated from dying in late June/early July and floating to shore. Other CLP beds remain and these beds probably produced dying, floating weeds that could be a nuisance depending upon where you live on the lake and the wind direction. These remaining beds will be treated as we gain control of the initial beds treated( 1-3 years). So over time we will be able to control CLP.
The floating weeds we all experienced in late July, August and into September were not Curly Leaf Pondweed. The late summer floating weeds will be discussed next.
Late July/ August /September Floating Weeds
In order to better understand the late season floating weeds issue, we contacted Lake Management Inc. Lake Management has been treating weeds on Forest Lake for many years and is very familiar with the lake. They indicated that Coontail and Canada Waterweed (Elodea) are two common weeds on Forest Lake that have no or very weak root structures and will break away and float with boat traffic or heavy winds. This past summer we have had a large number of severe storms and a lot of days with heavy and constant winds. Lake Management feels that these storms and winds caused the high incidence of floating weeds.
Algae Blooms and Low Water Clarity
This past summer we have had a lot of algae blooms. It varied by lake but Lake 1 was probably the worst. As a result water clarity was very low. Algae blooms require warm water and a source of phosphorus. The source of phosphorus from dying Curly Leaf Pondweed was significantly reduced because of the 155 acre treatment program. It was the opinion of the Watershed District that the heavy rains, especially following two drought years, probably washed a significant amount of nutrients into the lake. The nutrients when combined with the above average water temperatures probably instigated the severe algae blooms we experienced. In addition the WSD indicated that high winds like we experienced can stir up phosphorus from the lake bottom of shallow lakes similar to Lake 1. If you recall, the previous two summers were very dry with few heavy storms and very little run off into the lake. Last year (2009 summer) was one of the best years for water clarity without mid to late season floating weed issues.
This coming year we plan to consult and work with the Watershed District to better understand our algae and water clarity issues to see what options are available to reduce algae blooms and improve water clarity. Bald Eagle lake in White Bear had an algae and water clarity issue which they addressed with the WSD’s help and reportedly have made progress in reducing phosphorus inflow .
This is all the information we have at this time. We hope that this Newsletter begins to shed some light on what happened this summer to our lake.
The FLLA Board Members
Steve Schmaltz, President
This has not been a good summer for the lake when you consider weeds floating to shore, water clarity and algae blooms. We have done some checking and want to share with you what we have discovered. The information will be presented in three segments:
1. Curly Leaf Pondweed which is an invasive species and can be a problem in late June/early July.
2. Late July/August weeds floating to shore.
3. Algae blooms and poor water clarity.
Curly Leaf Pondweed (CLP)
In Forest Lake Curly Leaf Pondweed (CLP) is the most common weed . It is also an invasive species. This means if left uncontrolled it will spread and dominate other native weed species of which there are 23 in Forest Lake.
CLP grows extremely fast to form a dense mat like structure at the surface which blocks light and chokes out other native aquatic weed species. The dense weed structure also interferes with recreational use of that area by swimmers, water skiers , tubing, personal watercraft and even sail boating. In late June/early July CLP dies and floats to shore clogging shorelines. As it decays, it releases phosphorus which with warm water temperatures stimulates algae blooms and reduces water clarity.
A top priority for the FLLA is to control and reduce CLP in Forest Lake. Working with the city, the DNR and the Watershed District, 155 acres of CLP weed beds were treated in early May before aggressive growth started. 63 acres were treated on Lake 3, 37 acres on Lake 2, and 55 acres on Lake 1. The weed beds treated were “dominant CLP” which means they were 75% plus CLP. Thus, tons of CLP were eliminated from dying in late June/early July and floating to shore. Other CLP beds remain and these beds probably produced dying, floating weeds that could be a nuisance depending upon where you live on the lake and the wind direction. These remaining beds will be treated as we gain control of the initial beds treated( 1-3 years). So over time we will be able to control CLP.
The floating weeds we all experienced in late July, August and into September were not Curly Leaf Pondweed. The late summer floating weeds will be discussed next.
Late July/ August /September Floating Weeds
In order to better understand the late season floating weeds issue, we contacted Lake Management Inc. Lake Management has been treating weeds on Forest Lake for many years and is very familiar with the lake. They indicated that Coontail and Canada Waterweed (Elodea) are two common weeds on Forest Lake that have no or very weak root structures and will break away and float with boat traffic or heavy winds. This past summer we have had a large number of severe storms and a lot of days with heavy and constant winds. Lake Management feels that these storms and winds caused the high incidence of floating weeds.
Algae Blooms and Low Water Clarity
This past summer we have had a lot of algae blooms. It varied by lake but Lake 1 was probably the worst. As a result water clarity was very low. Algae blooms require warm water and a source of phosphorus. The source of phosphorus from dying Curly Leaf Pondweed was significantly reduced because of the 155 acre treatment program. It was the opinion of the Watershed District that the heavy rains, especially following two drought years, probably washed a significant amount of nutrients into the lake. The nutrients when combined with the above average water temperatures probably instigated the severe algae blooms we experienced. In addition the WSD indicated that high winds like we experienced can stir up phosphorus from the lake bottom of shallow lakes similar to Lake 1. If you recall, the previous two summers were very dry with few heavy storms and very little run off into the lake. Last year (2009 summer) was one of the best years for water clarity without mid to late season floating weed issues.
This coming year we plan to consult and work with the Watershed District to better understand our algae and water clarity issues to see what options are available to reduce algae blooms and improve water clarity. Bald Eagle lake in White Bear had an algae and water clarity issue which they addressed with the WSD’s help and reportedly have made progress in reducing phosphorus inflow .
This is all the information we have at this time. We hope that this Newsletter begins to shed some light on what happened this summer to our lake.
The FLLA Board Members
Steve Schmaltz, President
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