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Lake Quality and Dredging Update
From Kevin Wetzel, Dredging Committee Chairman
I have received two letters, one dated February 19, 2009 and June
10, 2009 from Ledy Design Group and FTC&H, the engineering group who
were hired last year to perform the broad based engineering study of
Lake Columbia to determine water quality issues, investigate weed
types and treatment methods, potential areas where dredging may be
required, silt and sediment concentrations throughout the lake and
chemical buildup (typically from lawn and farm fertilization) and to
provide recommendations as to how to best correct and maintain
problems throughout the lake.
February 19, 2009 Letter Summary
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1. |
FTC&H visited the lake and did a visual inspection
of the of Goose Creek & stated that sediment and debris
are the major source of buildup in Lake Columbia, the
South Canal specifically. |
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2. |
The stream channel is stable and at the time of the
visual inspection, water was moving well and was clear
but included a few blockages. |
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3. |
Minor erosion of the channel walls is occurring at a
natural level with approximately 120 cubic yards of
sediment entering Lake Columbia annually. |
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4. |
Evidence of large amounts of debris (primarily
leaves and other vegetation) enter Lake Columbia from
the channel annually. |
June 10, 2009 Letter Summary
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1. |
FTC&H entered Lake Columbia on a boat and took
samples of water, sediment, vegetation, etc. to perform
their “wet weather testing” of the existing conditions. |
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2. |
Water samples were collected from the north end,
center and south canal to determine concentrations of
total phosphorus and chlorophyll-a. |
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3. |
The lake was well mixed at the time of the sampling
and the temperature was consistent throughout. |
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4. |
Water quality was relatively high at the time of the
samplings. |
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5. |
These samplings were the first of two. The second
sampling “dry weather testing” will be take sometime in
August and the results of the initial testing are
inconclusive until the second sampling is taken and
comparisons of the two samples are made. |
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6. |
Concentrations of Eurasian Milfoil was observed in
Stump Bay and in the South Canal. |
One of the issues we are trying to determine is where all of the
sediment came from after the last dredging project in the south
canal. Within 3-4 years after the last dredging project, the poor
conditions including deep sediment and silt returned to that area to
a similar condition as existed prior to the dredging project of
1997/98. Prior to that dredging project, it took over 30 years to
accumulate and contributes to the sediment and accelerated weed
growth throughout the lake.
I will keep you informed as we get closer to completion of the
engineering study. If you have questions, please contact me at
kevin@cmcmichigan.com and
I will do my best to respond in a timely fashion.
Kevin Wetzel
Dredging Committee Chairman
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