• Lake Retreat had fairly clear water with low nutrient concentrations and low algal growth.
• Long-term trends suggest that water quality in Lake Retreat has been declining over time, with increasing nitrogen and phosphorus concentrations, and shallower Secchi depths.
• Nitrogen-to-phosphorus (N:P) ratios were above 25 for the entire monitoring season. This indicates a low likelihood for the algal community to be dominated by cyanobacteria (which have the ability to produce toxins).
• Consistent with previous years, Lake Retreat had a noticeable shift in August. Before that time, it had very deep Secchi depths (clearer water) and nitrogen-to-phosphorus (N:P) ratios were above 75. After mid-August, it had much shallower Secchi depths and decreased nitrogen-to-phosphorus (N:P) ratios.
• No algal blooms were reported for toxin testing in 2024.
This bathymetric map shows contour lines of equal depth, similar to a topographic map would for mountains and valleys. The red 'X' marks the location where water quality samples are taken.
This map shows the area of the watershed relative to the area of the lake. Generally speaking, the larger a watershed is relative to a lake, the greater the influence land use practices on lake water quality.
The average of these three TSI indicators during the growing season can be used
to place lakes in one of three broad categories:
<40 = oligotrophic (low productivity),
40 to 50 = mesotrophic (moderate productivity)
>50 = eutrophic (highly productive).
