WATER QUALITY REPORT

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.

For those who enjoy technical data, Lake Poinsett’s
water quality data can be found on the SD DENR
website. 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.
Click 
Water Quality Monitoring Access Portal.

WQ Map: DENR Watershed Protection Program

WATER SAMPLE AVERAGE 2016-2020


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.You can also view these graphs on the SD DENR Website or by clicking the
WATER QUALITY DASHBOARD
.

TOTAL PHOSPHORUS

Lake Poinsett’s Average: 0.140 mg/L

Regional Lakes’ Average: 0.192 mg/L

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.

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.

PHOSPHORUS

WQ CHART.jpg

TOTAL NITROGEN

Lake Poinsett’s Average: 1.507 mg/L

Regional Lakes’ Average: 2.024 mg/L

SUMMARY

Total Nitrogen data shows consistent lower numbers. On all counts Lake Poinsett faired better than regional lakes.

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.

NITROGEN

WQ CHART2.jpg

CHLOROPHYLL-A

Lake Poinsett’s Average: 20.506 (ppb) parts per billion

Regional Lakes’ Average: 35.527 (ppb) parts per billion

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.

0-10 Low Risk    10-50 Moderate Risk    Over 50 High Risk for adverse health effects

Values are from the World Health Organization

WQ CHART3.jpg

TRANSPARENCY (Secchi)

Lake Poinsett’s Average: (2.154 meters or 7.07 feet)

Regional Lakes’ Average: (1.280 meters or 4.2 feet)

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.

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.

WQ CHART4.jpg