Lynn Lake
Day County, South Dakota57 acresView mapDirections
SD DANR publishes the water-quality measurements for Lynn Lake. Here is what has been measured.
- Impaired · Mercury
- Limited data
Lynn Lake in Day County, South Dakota has water-quality measurements published by SD DANR, shown here as reported. Chlorophyll-a (algae): 6.9 µg/L. Surface area: 57 acres.
Lynn Lake is a 57-acre lake in Day County, South Dakota.
Source: EPA Water Quality Portal sampling records, SD DANR, last sampled 2017-06-28. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Lynn Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Lynn Lake is safe to swim in today is a call for the South Dakota Department of Agriculture and Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lynn Lake
These are the measurements SD DANR publishes for Lynn Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Chlorophyll-a 6.9 µg/L.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | 6.9µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
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Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
57 acres
Shoreline
1.7 mi
No bathymetric survey has been published for Lynn Lake, so its depth is not documented here.
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Fishing Lynn Lake
EPA Impairment Status
Lynn Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Aquatic life.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit SD-JA-L-LYNN_01 · Official waterbody report
Nearby Lakes in Day County
Frequently asked questions about Lynn Lake
Where is Lynn Lake?
- Lynn Lake is a lake in Day County, South Dakota. Its water-quality measurements are published by SD DANR and shown on this page as reported.
What is the water quality of Lynn Lake?
- Lynn Lake in Day County, South Dakota has water-quality measurements published by SD DANR, shown here as reported. Chlorophyll-a (algae): 6.9 µg/L. Surface area: 57 acres.
Is Lynn Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Lynn Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
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Where this data comes from
Measurements for Lynn Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database