Beaver Lake is a 34-acre productive, nutrient-rich eutrophic lake in Dallas County, Iowa. Water quality is graded F based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 1 other monitored lakes in Dallas County, Beaver Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-30. Grade methodology: LakeGrade methodology.
Watch Beaver Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 1.9 ft of visibility. Chlorophyll-a: 62.2 µg/L. Trophic State Index: 70.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.9 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 62.2 µg/L | F |
| Trophic State Index (TSI) | 70 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 34 acres |
| Public Access | Yes |
Where to stay near Beaver Lake
Compare lakeside cabins, hotels, and vacation rentals near Beaver Lake in Dallas County, Iowa — 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.
Top-rated places to stay near Beaver Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Beaver Lake?
Get lake water-quality report cards plus the best cabin & lodging deals near Beaver Lake — straight to your inbox. No spam, unsubscribe anytime.
Planning a whole trip? See where to stay at Iowa’s top lakes →
Fishing Beaver Lake
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.04 m/yr | 5 |
| Chlorophyll-a | → Stable | -0.63 µg/L/yr | 5 |
Recreation & Access
Water Temperature
Beaver Lake averages about 77°F at the surface in summer, usually warmest in Jul (about 81°F) and coldest in May (about 70°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 39 field readings (2010–2023) via the EPA Water Quality Portal. See the full Beaver Lake water temperature breakdown →
Location & Depth Map
Free interactive depth-contour map of Beaver Lake, reaching a maximum surveyed depth of 39 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
County Ranking
Ranked #2 of 2 lakes in Dallas County
Cleaner Lakes Within 30 Miles
Beaver Lake holds Grade F. 3 nearby lakes hold higher grades.
- BDale Maffitt ReservoirDallas County · 21.8 mi · Two grade letters higher (F → B)
- DSpringbrook LakeGuthrie County · 21.3 mi · Higher grade (F → D)
- DNodaway LakeAdair County · 22.4 mi · Higher grade (F → D)
Nearby Lakes in Dallas County
Explore Beaver Lake across LakeGrade
More Iowa Lake Rankings
Other Grade F Lakes in Iowa
Eutrophic Lakes in Iowa
More records, surveys & data sources
Reservoir Info (USACE NID)
Beaver Lake is a man-made reservoir impounded by the Beaver Lake Dam (completed 1990), built primarily for recreation on the TR-BEAR CREEK; earth-type dam, 43 ft tall and 666 ft long.
- Surface area
- 34 ac
- Normal storage
- 319 ac-ft
- Max storage
- 696 ac-ft
- Drainage area
- 1.61 sq mi
- Hazard class
- Significant
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA02498 · Operator website
EPA Impairment Status
Beaver 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 IA 04-RAC-1182 · Official waterbody report
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Beaver Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Dexter City Of StpDexter · 1.9 mi away · NPDES IA0058661Recent violation
- Redfield City Of StpRedfield · 3.3 mi away · NPDES IA0036099Recent violation
- Diamondhead LakeDexter · 3.4 mi away · NPDES IA0068381Recent violation
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.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Grading methodology based on Metropolitan Council standards
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2024-09-30
Monitoring stations: 1