WATER QUALITY REPORT
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Lake Poinsett Association partnered with the
East Dakota Water Development District
(Brookings) and the SD DENR Watershed
Protection Program for volunteer training and
support on water quality sampling. The state
monitors our lake water on a rotation basis
with other lakes and streams, but there are
several years where no testing is done.
Our volunteer water sampling not only fills in
those gap years with consistent data, but we
also test more areas around the lake. This
creates a larger snapshot of vital information
for researchers to track lake health trends.
Lake Poinsett’s water quality data can be
found on the SD DENR website by opening the
Water Quality Monitoring Access Portal.
It allows you to view waterbodies and click on
their monitoring stations (Dots) to view recent
data. Dots on the map represent locations
where water quality samples were collected.
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For those who enjoy technical data, click open the SD DENR WATER QUALITY DASHBOARD with detailed graphs illustrating the lake’s past 5-year statistics for Total Nitrogen, Total Phosphorus, Chlorophyll-a, E.coli, and Transparency (Secchi). The graphed dots are Lake Poinsett’s water sample test results and for comparison the horizontal line represents all Northeast Regional Lakes Average. If the dots are below this line, it means Lake Poinsett has less of that pollutant, on average, than other lakes in the region.
WATER SAMPLE AVERAGE BETWEEN FOR 2016-2020
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TOTAL PHOSPHORUS
Lake Poinsett’s Average: 0.140 mg/L
Regional Lakes’ Average: 0.192 mg/L
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SUMMARY
Total Phosphorus data shows plenty of variance over the past years. High levels of phosphorus lead to excessive algae growth which produces harmful toxins to human and animal health and reduces water recreation due to unpleasant odors and unappealing water. Once phosphorus enters lake water there is little that can be done to remove it, except allowing it to settle undisturbed on the lake bottom.
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Additional and consistent monitoring over a longer period will provide a clearer picture of water testing results. Each year lake conditions affect all water quality samples differently such as lake water temperatures, cooler or warmer summers, high or low water levels, wet or dry years, and calm or windy days.
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PHOSPHORUS
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TOTAL NITROGEN
Lake Poinsett’s Average: 1.507 mg/L
Regional Lakes’ Average: 2.024 mg/L
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SUMMARY
Total Nitrogen data shows consistent lower numbers. On all counts Lake Poinsett faired better than regional lakes.
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Additional and consistent monitoring over a longer period will provide a clearer picture of water testing results. Each year lake conditions affect all water quality samples differently such as lake water temperatures, cooler or warmer summers, high or low water levels, wet or dry years, and calm or windy days.
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NITROGEN
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CHLOROPHYLL-A
Lake Poinsett’s Average: 20.506 (ppb) parts per billion
Regional Lakes’ Average: 35.527 (ppb) parts per billion
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SUMMARY
In the last 5 years, Lake Poinsett has generally had chlorophyll-a results below the regional average. However, the lake does produce significant algae blooms in some years that are considered a high risk for producing algae toxins. Additional monitoring for chlorophyll-a and algae toxins would provide a clearer picture of how common and severe algae blooms are on Lake Poinsett.
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0-10 Low Risk 10-50 Moderate Risk Over 50 High Risk for adverse health effects
Values are from the World Health Organization
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TRANSPARENCY (Secchi)
Lake Poinsett’s Average: (2.154 meters or 7.07 feet)
Regional Lakes’ Average: (1.280 meters or 4.2 feet)
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SUMMARY
High numbers are very good in this category. It indicates the amount of light penetration into the water. A low clarity reading reflects excess algae or sediment. Nutrient and sediment pollution are the main causes of poor water clarity. Excess nutrients and suspended sediment can fuel the growth of water-clouding algae.
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Additional and consistent monitoring over a longer period will provide a clearer picture of water testing results. Each year lake conditions affect all water quality samples differently such as lake water temperatures, cooler or warmer summers, high or low water levels, wet or dry years, and calm or windy days.
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PHOSPHORUS - SD DENR Water Quality Monitoring Access Portal 2020
NITROGEN - SD DENR Water Quality Monitoring Access Portal 2020
CHLOROPHYLL-a - SD DENR Water Quality Monitoring Access Portal 2020
TRANSPARENCY - SD DENR Water Quality Monitoring Access Portal 2020