Beaver Dam Lake
Beaver Dam Lake in Dodge County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 1 ft visibility. Phosphorus: 230.5 µg/L. Surface area: 6542 acres.
- Clarity
- 1 ft
- Area
- 6,542 acres
- Type
- Hypereutrophic
- Trend
- ↓ Declining
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Beaver Dam Lake →
Next lake in Dodge County
Beaver Dam Lake is a 6,542-acre highly nutrient-loaded hypereutrophic lake in Dodge County, Wisconsin. Water quality is graded D based on 1 sampling years through 2026. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 4 public boat landings. Compared to the 2 other monitored lakes in Dodge County, Beaver Dam Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-30. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyElevated nutrients
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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 1 ft of visibility. Phosphorus level: 230.5 µg/L. Trophic State Index: 80.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1 ft | Not graded |
| Phosphorus | 230.5 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 80 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Beaver Dam Lake
Compare lakeside cabins, hotels, and vacation rentals near Beaver Dam Lake in Dodge County, Wisconsin — 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 Beaver Dam Lake are listed below.
Top-rated places to stay near Beaver Dam Lake
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Planning a trip? Cabins and lodging at Beaver Dam Lake → · more Wisconsin lake trips
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 6,542 acres |
| Public Access | Yes |
No bathymetric survey has been published for Beaver Dam Lake, so its depth is not documented here.
Recreation & Access
- Derge County ParkPublic
- Hickory BayPublic
- Beaver Dam LakePublic
- Fish CampPublic
Fishing Beaver Dam Lake
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Beaver Dam Lake covering fish populations, stocking, water quality, and management. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2021Beaver Dam Lake comprehensive survey, 2021Comprehensive Survey · WI DNR · 2021 (PDF)
Water Quality Trend: ↓ Declining
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.065 m/yr | 7 |
| Phosphorus | → Stable | +2.86 µg/L/yr | 6 |
Reservoir Info (USACE NID)
Beaver Dam Lake is a man-made reservoir impounded by the Upper Beaver Dam (completed 1840), built primarily for recreation on the BEAVER DAM RIVER; earth-type dam, 20 ft tall and 100 ft long.
- Surface area
- 6,542 ac
- Normal storage
- 30,677 ac-ft
- Max storage
- 57,000 ac-ft
- Drainage area
- 157 sq mi
- Hazard class
- High
- Owner
- City Of Beaver Dam
Source: USACE National Inventory of Dams, NID ID WI00119 · Operator website
EPA Impairment Status
Beaver Dam 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 WI10001258 · Official waterbody report
County Ranking
Ranked #2 of 3 lakes in Dodge County
Nearby Lakes With Higher Grades
Beaver Dam Lake holds Grade D. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Dodge County
Frequently asked questions about Beaver Dam Lake
What is the water quality grade for Beaver Dam Lake?
- Beaver Dam Lake in Dodge County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 1 ft visibility. Phosphorus: 230.5 µg/L. Surface area: 6542 acres.
Is Beaver Dam Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Beaver Dam Lake has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
Are there boat ramps on Beaver Dam Lake?
- Beaver Dam Lake has 4 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Derge County Park, Hickory Bay, Beaver Dam Lake, Fish Camp. Public access is listed as yes.
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Where this data comes from
146 measurements from 4 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX146 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (4)
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
Named boat-access points from the USGS National Boat Ramps inventory