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2023 WATER QUALITY (Jan 2024 Report - Prepared by John Willson and Gary Nielsen)

In 2023 Gary Nielsen and John Willson continued the water sampling that has been done annually for over 20 years. During the summer, forty-two phosphorus samples and water clarity recordings were collected over the period May 24th to October 30th inclusive; six samples from each of seven basins in the lake. The phosphorus test results from the Lake Partner program are not available yet.

During the spring, summer and fall of 2023, Charleston Lake once again experienced excellent water clarity (Average Secchi depth 8.30m); this value is higher than the last 5 year average of 6.66m and closer to the 2009-2013 period when the zebra mussel colonization was at its peak. When compared to the first five years (2000 to 2004 inclusive) of clarity data the improvement is remarkable. The mean water clarity value for the first five years is 4.30m. The largest part of the improvement in clarity is the result of the zebra mussel colonization of the lake, but that appears to have been stable for a number of years and the results continue to improve.  Donaldson Bay had the highest average clarity at 9.32m, ranging to Southern Waters at 7.15m average

Water clarity has improved so much in recent years that the mean value for the 22-year period of record (6.252 m) places Charleston Lake in the oligotrophic category for the entire time frame, despite the fact that for the first five years of that period (2000 to 2004 inclusive) the water clarity averaged only 4.305 m. Oligotrophic lakes have a water clarity > 5.0 metres.

Through a combination of good luck and good management we have seen Charleston Lake return to near pristine conditions from where it was a generation ago.  We can't take it for granted but we can enjoy the result and do what we can to make sure it stays this way.

2023 WATER QUALITY RESULTS.png

HISTORICAL WATER QUALITY REPORTS

2022 WATER QUALITY  (Jan 2023 report - prepared by John Willson and Gary Nielsen)
In 2022 Gary Nielsen and John Willson took on the water sampling that has been done annually for over
20 years. During the summer, forty-two phosphorus samples and water clarity recordings were collected
over the period May 25th to October 30th inclusive; six samples from each of seven basins in the lake.


During the spring, summer and fall of 2022, Charleston Lake once again experienced excellent water
clarity (Average Secchi depth 7.455m); this value is higher than the last 5 year average of 6.51m and
closer to the 2009-2013 period when the zebra mussel colonization was at its peak. When compared to
the first five years (2000 to 2004 inclusive) of clarity data the improvement is remarkable. The mean
water clarity value for the first five years is 4.305 m. The largest part of the improvement in clarity is the
result of the zebra mussel colonization of the lake, but that appears to have been stable for a number of
years and the results continue to improve. Donaldson Bay had the highest average clarity at 8.48m,
ranging to Deep Water (Runnings Bay) at 6.87m average.


Water clarity has improved so much in recent years that the mean value for the 21-year period of record
(6.159 m) places Charleston Lake in the oligotrophic category for the entire time frame, despite the fact
that for the first five years of that period (2000 to 2004 inclusive) the water clarity averaged only 4.305
m. Oligotrophic lakes have a water clarity greater than 5.0 metres.


The 2022 total phosphorus from the MOECP Lake Partner Program showed a mean average of 8.93 ug/L
compared to the previous 5 test periods (2016-2021) of 9.03 ug/L. These levels are below (better) than
the Provincial Water Quality Objective of 10 ug/L, and have been for over 10 years. The period of 2000-
2004 had a whole lake mean value of 14.027 ug/L, so the last 10 years have shown a remarkable
improvement. A big part of the initial improvement was the result of the zebra mussel colonization of
the lake, but that appears to have been stable and/or declining for a number of years and the results
continue to improve. The mean values (2022) for the various basins are 7.98 Donaldson Bay, 8.79 Deep
Water (Runnings Bay), 8.85 Big Water, 8.92 Eastern Water, 8.95 Webster Bay, 9.48 Eastern Water, 9.56
Goose Island.


Charleston Lake has reached a new steady-state equilibrium with respect to total phosphorus
concentration for the period 2009- 2022 inclusive that clearly places Charleston Lake in the oligotrophic
category for this parameter.


As residents of the lake we should take pride in the fact that our lake is in such great shape.  Through a
combination of good luck and good management we have seen Charleston Lake return to near pristine
conditions from where it was a generation ago.  We can't take it for granted but we can enjoy the result
and do what we can to make sure it stays this way.


The full 2022 results and report can be see by clicking here.



2021 WATER QUALITY - (Jan 2022 report Prepared by Reginald Genge)


After a brief hiatus in 2020, an intensive water quality survey was completed on Charleston Lake during the summer of 2021. During the summer, forty-two phosphorus samples and water clarity recordings were collected over the period May 17th to October 20th inclusive; six samples from each of seven basins in the lake. This work is a continuation of the yearly monitoring effort for water clarity and phosphorus concentrations conducted since the year 2000. The sample sites are located in Big Water, Deep Water (Runnings Bay), Donaldson Bay, Webster Bay, north of Goose Island, Eastern Waters and Southern Waters. In addition, surface to bottom dissolved oxygen and temperature profiles were recorded at all sites for the September 3rd, September 25th and October 20th survey dates; the last time this work was completed was the year 2015.

As of the writing of this newsletter the analysis for total phosphorus was not yet available from the MOECP Lake Partner Program. These results will be reported upon, inclusive of all the temperature and oxygen recordings, in the final report to the Charleston Lake Association in the spring of 2022.
During the spring, summer and fall of 2021, Charleston Lake once again experienced excellent water clarity (Average Secchi depth 6.873 m); this value is within the year-to-year natural variability for water clarity. When the first five years (2000 to 2004 inclusive) of clarity data is compared against the last five years (2015 to 2021 inclusive) of data, the improvement is remarkable. The mean water clarity value for the first five years is 4.305 m while for the most recent five-years of survey it is 6.377 m; an improvement of 2.072 m. The great improvement in clarity is the result of the zebra mussel colonization of the lake.

Water clarity has improved so much in recent years that the mean value for the 21-year period of record (6.097 m) places Charleston Lake in the oligotrophic category for the entire time frame, despite the fact that for the first five years of that period (2000 to 2004 inclusive) the water clarity averaged only 4.305 m. Oligotrophic lakes have a water clarity > 5.0 metres.

Surface to bottom oxygen and temperature profiles are conducted to document, among other things, the amount of water column suitable as lake trout habitat. The concern for this relates to nutrient loadings. The more phosphorus, the poorer the water clarity and the greater the rate of oxygen depletion from the cold deep waters and hence the loss of lake trout habitat. The in situ profiles show that there has been an improvement in deep water oxygen concentrations in recent years (2007, 2009, 2012, 2015 and 2021) when compared with data from the years 2000 and 2002.

The 2021 sampling shows that optimal conditions for lake trout exist at all the sites for each of the survey dates with the exception of Southern Waters. Southern Waters is too shallow to support lake trout and the oxygen conditions below the thermocline become depleted by mid-summer.

I must express my thanks to CLA members Gary Nielsen and John Willson for assisting in the 2021survey. They are now trained and will carry on with this survey work in the future. I am confident the continued monitoring effort is in good hands.

2020 WATER QUALITY- JAN 2021 REPORT

Not tested due to COVID

2019 WATER QUALITY- JAN 2020 REPORT

(see full report)

 

Water clarity is recorded at each of the seven sample sites on the lake on six dates between May 1st and the end of October each year. There is an extensive database on Charleston Lake for this parameter extending back into the mid-1970s; since the year 2000 the seven basins of Charleston have been monitored for water clarity, phosphorus and calcium concentrations and periodically surface to bottom water column oxygen and temperature values. These are reported on annually. As of the writing of this article, the phosphorus and calcium analytical data for the summer of 2019 is not yet available from the Ministry of Environment, Conservation and Parks.

The mean water clarity value (Secchi disc depth) for the lake as a whole in 2019 is 6.415 metres (42 recordings). Since and including the year 2014, Charleston Lake has experienced a decline in water clarity when compared with values for the period 2009 to 2013 inclusive.  The whole lake average water clarity for the period 2009 to 2013 inclusive was 7.56m; for the period 2014 to 2019 inclusive, the average water clarity value was 6.32m. The mean whole-lake average water clarity value for all twenty years combined (years 2000 to 2019) is 6.058 metres.

The 20 years of findings are summarized in the graph.

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