Jonathan Lake
Carver County, Minnesota31 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Jonathan Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
Jonathan Lake in Carver County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 1.6 ft visibility. Phosphorus: 157.5 µg/L. Chlorophyll-a (algae): 80 µg/L. Surface area: 31 acres.
Jonathan Lake is a 31-acre highly nutrient-loaded hypereutrophic lake in Carver County, Minnesota. Water clarity is improving over recent sampling years. The lake supports 3 documented fish species including black bullhead, bluegill, and green sunfish. No public access — the lake is private or restricted. Compared to the 37 other monitored lakes in Carver County, Jonathan Lake ranks #19 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-06. Methodology: how these readings are compared.
What Jonathan Lake is good for
From access and monitoring records, not editorial picks.
- Fishing3 species recorded
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Jonathan Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Jonathan Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Jonathan Lake
These are the measurements Minnesota PCA publishes for Jonathan Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1.6 ft of visibility. Phosphorus 157.5 µg/L. Chlorophyll-a 80 µg/L. TSI 74.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 158µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 80µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 74 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Jonathan Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Jonathan Lake typically sits around 63°F at the surface in October. Summer average is about 76°F. Usually warmest in Jul (about 78°F) and coldest in Feb (about 35°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (35°F) to its warmest (78°F).
Typical surface water temperature by month, from 234 field readings (2010–2025) via the EPA Water Quality Portal.
Lake Details
Surface area
31 acres
Public access
No
Listed by Minnesota PCA
No bathymetric survey has been published for Jonathan Lake, so its depth is not documented here.
Stays via Stay22
Stays near Jonathan Lake
Compare lakeside cabins, hotels, and vacation rentals near Jonathan Lake in Carver County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Jonathan Lake are listed below.
Top-rated places to stay near Jonathan Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Jonathan Lake
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Stable+1.64 µg/L/yr6 years
Chlorophyll-a
Worsening+4.17 µg/L/yr6 years
Reservoir Info (USACE NID)
Jonathan Lake is a man-made reservoir impounded by the Mcknight Lake, built primarily for flood risk reduction on the Chaska East Creek; earth-type dam, 8 ft tall.
- Surface area
- 31 ac
- Normal storage
- 82 ac-ft
- Max storage
- 82 ac-ft
- Drainage area
- 5.93 sq mi
- Hazard class
- Low
- Owner
- City of Chaska
Source: USACE National Inventory of Dams, NID ID MN01263 · Operator website · Matched by proximity (0.38 km)
EPA Impairment Status
Jonathan 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: Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN10-0217-00 · Official waterbody report
Nearby Lakes in Carver County
Frequently asked questions about Jonathan Lake
Where is Jonathan Lake?
- Jonathan Lake is a lake in Carver County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Jonathan Lake?
- Jonathan Lake in Carver County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 1.6 ft visibility. Phosphorus: 157.5 µg/L. Chlorophyll-a (algae): 80 µg/L. Surface area: 31 acres.
Is Jonathan Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Jonathan Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Jonathan Lake?
- Jonathan Lake typically sits around 63°F at the surface in October, from 234 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
What fish are in Jonathan Lake?
- Fish species found in Jonathan Lake include black bullhead, bluegill, green sunfish. Jonathan Lake is located in Carver County, Minnesota.
Can I fish at Jonathan Lake?
- Public access to Jonathan Lake is listed as no on the lake record, so confirm before you make the trip. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
202 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA202 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake details from Minnesota DNR LakeFinder