Big Woods Lake
Big Woods Lake in Carver County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1.5 ft visibility. Phosphorus: 197 µg/L. Chlorophyll-a (algae): 113 µg/L. Surface area: 31 acres.
- Clarity
- 1.5 ft
- Typical in August
- 74°F
- Area
- 31 acres
- Type
- Hypereutrophic
- Trend
- ↑ Improving
- Public access
- No
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Big Woods Lake →
Next lake in Carver County
Big Woods Lake is a 31-acre highly nutrient-loaded hypereutrophic lake in Carver County, Minnesota. Water quality is graded F based on 2 sampling years through 2025. Overall water quality 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, Big Woods Lake ranks #24 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-06. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyAlgae risk
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
Very murky, less than 1.5 ft of visibility. Phosphorus level: 197 µg/L. Chlorophyll-a: 113 µg/L. Trophic State Index: 76.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.5 ft | Not graded |
| Phosphorus | 197 µg/L | Poor |
| Chlorophyll-a (Algae) | 113 µg/L | Poor |
| Trophic State Index (TSI) | 76 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Big Woods Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Woods 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 grade measures nutrients and algae, not lodging — cabins and rentals around Big Woods Lake are listed below.
Top-rated places to stay near Big Woods Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Big Woods Lake typically sits around 74°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 76°F) and coldest in Feb (about 36°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 253 field readings (2019–2025) via the EPA Water Quality Portal.
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 31 acres |
| Public Access | No |
No bathymetric survey has been published for Big Woods Lake, so its depth is not documented here.
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Big Woods Lake
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.019 m/yr | 6 |
| Phosphorus | ↑ Improving | -6.07 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +2.1 µg/L/yr | 6 |
Reservoir Info (USACE NID)
Big Woods Lake is a man-made reservoir impounded by the Ids (completed 1989), built primarily for flood risk reduction on the Chaska East Creek; earth-type dam, 20 ft tall.
- Surface area
- 31 ac
- Normal storage
- 89 ac-ft
- Max storage
- 453 ac-ft
- Drainage area
- 2.3 sq mi
- Hazard class
- Low
- Owner
- City of Chaska
Source: USACE National Inventory of Dams, NID ID MN01264 · Operator website · Matched by proximity (0.19 km)
EPA Impairment Status
Big Woods Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN10-0216-00 · Official waterbody report · Matched by proximity (0.72 km)
Regulated Pollution Sources Nearby
4 EPA-permitted facilities operate within about 5 miles of Big Woods Lake under Clean Water Act (NPDES) discharge permits.
- Lifecore Biomedical LlcChaska · 0.3 mi away · NPDES MN0060747
- Fsi InternationalChaska · 0.4 mi away · NPDES MN0068781
- Apex Manufacturing PlantChaska · 0.6 mi away · NPDES MN0067016
- Mclaughlin Gormley King CoChaska · 0.7 mi away · NPDES MN0058033
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #24 of 38 lakes in Carver County
Nearby Lakes With Higher Grades
Big Woods Lake holds Grade F. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Carver County
Frequently asked questions about Big Woods Lake
What is the water quality grade for Big Woods Lake?
- Big Woods Lake in Carver County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1.5 ft visibility. Phosphorus: 197 µg/L. Chlorophyll-a (algae): 113 µg/L. Surface area: 31 acres.
Is Big Woods Lake safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Big Woods Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 113 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Big Woods Lake?
- Big Woods Lake typically sits around 74°F at the surface in August, from 253 EPA Water Quality Portal field readings (2019–2025). That is a typical value for the month, not a live reading.
What fish are in Big Woods Lake?
- Fish species found in Big Woods Lake include black bullhead, bluegill, green sunfish. Big Woods Lake is located in Carver County, Minnesota.
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Where this data comes from
200 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
MNPCA200 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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake details from Minnesota DNR LakeFinder