Gustafson Lake
Buena Vista County, Iowa10 acresView mapDirections
Nutrients and algae run above the regional average.
- Eutrophic
- Impaired · Pathogens (E. coli, fecal)
- #3 of 3 in the county
- Public access
Gustafson Lake in Buena Vista County, Iowa has a water quality grade of D (Nutrient-rich). Water clarity: 2.3 ft visibility. Phosphorus: 48.2 µg/L. Chlorophyll-a (algae): 27 µg/L. Surface area: 9.7 acres.
- Clarity
- 2.3 ft
- Typical in August
- 77°F
- Area
- 10 acres
- Type
- Eutrophic
- Phosphorus
- 48.2 µg/L
- Chlorophyll-a
- 27 µg/L
- Trend
- ↑ Improving
- Public access
- Yes
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Stays near Gustafson Lake
Compare lakeside cabins, hotels, and vacation rentals near Gustafson Lake in Buena Vista 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Gustafson Lake are listed below.
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Watch Gustafson Lake’s letter
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Gustafson Lake is a 10-acre productive, nutrient-rich eutrophic lake in Buena Vista County, Iowa. Water quality is graded D based on 2 sampling years through 2022. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 2 other monitored lakes in Buena Vista County, Gustafson Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2022-09-12. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyBacteria advisory
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.
The D is nutrients and algae, not a swimming clearance. Gustafson Lake is listed impaired under Clean Water Act §303(d) (IR 5) for pathogens (E. coli, fecal), turbidity. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 2.3 ft of visibility. Phosphorus 48.2 µg/L. Chlorophyll-a 27 µg/L. TSI 63. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.3 ft | Not graded |
| Phosphorus | 48.2 µg/L | Fair |
| Chlorophyll-a (Algae) | 27 µg/L | Poor |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Temperature
Gustafson Lake typically sits around 77°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 79°F) and coldest in Jun (about 71°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 9 field readings (2018–2022) via the EPA Water Quality Portal. See the full Gustafson Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 10 acres |
| Public Access | Yes |
No bathymetric survey has been published for Gustafson Lake, so its depth is not documented here.
Fishing Gustafson Lake
Water Quality Trend: ↑ Improving
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.05 m/yr | 3 |
| Phosphorus | ↓ Declining | +1.4 µg/L/yr | 3 |
| Chlorophyll-a | ↑ Improving | -3.45 µg/L/yr | 3 |
Reservoir Info (USACE NID)
Gustafson Lake is a man-made reservoir impounded by the Gustafson Lake Dam (completed 1974), built primarily for recreation on the TR-LITTLE SIOUX RIVER; earth-type dam, 49 ft tall and 1,150 ft long.
- Surface area
- 9.7 ac
- Normal storage
- 90 ac-ft
- Max storage
- 176 ac-ft
- Drainage area
- 0.36 sq mi
- Hazard class
- Significant
- Owner
- Iowa Department of Transportation
All listed purposes: Recreation;Other.
Source: USACE National Inventory of Dams, NID ID IA02159 · Operator website
EPA Impairment Status
Gustafson Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit IA 06-LSR-1625 · Official waterbody report
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Gustafson Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Sioux Rapids City Of StpSioux Rapids · 1.3 mi away · NPDES IA0042951Recent violation
- Rembrandt Enterprises, Inc.Rembrandt · 3.9 mi away · NPDES IA0076554Recent violation
- Rembrandt City Of StpRembrandt · 4.2 mi away · NPDES IA0033219Recent 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.
County Ranking
Ranked #3 of 3 lakes in Buena Vista County
Nearby Lakes With Higher Grades
Gustafson Lake holds Grade D. 3 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 Buena Vista County
Frequently asked questions about Gustafson Lake
Where is Gustafson Lake?
- Gustafson Lake is a lake in Buena Vista County, Iowa. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Gustafson Lake?
- Gustafson Lake in Buena Vista County, Iowa has a water quality grade of D (Nutrient-rich). Water clarity: 2.3 ft visibility. Phosphorus: 48.2 µg/L. Chlorophyll-a (algae): 27 µg/L. Surface area: 9.7 acres.
Is Gustafson Lake safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Gustafson Lake is listed impaired under Clean Water Act §303(d) (IR 5) for pathogens (E. coli, fecal), turbidity. Check local advisories before you swim.
What is the water temperature of Gustafson Lake?
- Gustafson Lake typically sits around 77°F at the surface in August, from 9 EPA Water Quality Portal field readings (2018–2022). That is a typical value for the month, not a live reading.
Explore Gustafson Lake across LakeQuality
More Iowa Lake Rankings
Other Grade D Lakes in Iowa
Eutrophic Lakes in Iowa
Where this data comes from
36 measurements from 1 monitoring station, 2020–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX36 samples · 2020–2022
Analytical methods
- Unknown
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- ISU modification of APHA 2130-B
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)