Arrowhead Lake is a 110-acre productive, nutrient-rich eutrophic lake in Sac County, Iowa. Water quality is graded C 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 6 public boat landings. Compared to the 1 other monitored lakes in Sac County, Arrowhead Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-04. Grade methodology: LakeGrade methodology.
Watch Arrowhead Lake water quality
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 5.6 ft. Chlorophyll-a: 7.1 µg/L. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.6 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 7.1 µg/L | B |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 110 acres |
| Public Access | Yes |
Where to stay near Arrowhead Lake
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Fishing Arrowhead Lake
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.016 m/yr | 5 |
| Chlorophyll-a | ↑ Improving | -4.99 µg/L/yr | 5 |
Recreation & Access
Water Temperature
Arrowhead Lake averages about 78°F at the surface in summer, usually warmest in Jul (about 80°F) and coldest in May (about 64°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 29 field readings (2010–2023) via the EPA Water Quality Portal. See the full Arrowhead Lake water temperature breakdown →
Location & Depth Map
Free interactive depth-contour map of Arrowhead Lake, reaching a maximum surveyed depth of 22 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
County Ranking
Ranked #1 of 2 lakes in Sac County
Nearby Lakes in Sac County
Explore Arrowhead Lake across LakeGrade
More Iowa Lake Rankings
Other Grade C Lakes in Iowa
Eutrophic Lakes in Iowa
More records, surveys & data sources
Reservoir Info (USACE NID)
Arrowhead Lake is a man-made reservoir impounded by the Provost Bay Dam, built primarily for other on the unnamed tributary; earth-type dam, 10 ft tall and 650 ft long.
- Surface area
- 110 ac
- Max storage
- 257 ac-ft
- Drainage area
- 0.54 sq mi
- Hazard class
- Low
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA04396 · Operator website · Matched by proximity (0.67 km)
EPA Impairment Status
Arrowhead Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 04-RAC-1134 · Official waterbody report · Matched by proximity (2.12 km)
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Arrowhead Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Lake View City Of StpLake View · 1.1 mi away · NPDES IA0041998Recent violation
- Wall Lake City Of StpWall Lake · 3.1 mi away · NPDES IA0033065Recent violation
- Western Iowa Energy, LlcWall Lake · 3.5 mi away · NPDES IA0079855Recent 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: 2024-09-04
Monitoring stations: 1