Springbrook Lake is a 12-acre productive, nutrient-rich eutrophic lake in Guthrie County, Iowa. Water quality is graded D based on 2 sampling years through 2024. Water clarity is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-04. Grade methodology: LakeGrade methodology.
Watch Springbrook Lake water quality
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Swimming Safety
Based on E. coli testing, Springbrook Lake occasionally exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 7.3% of 110 samples across 7 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Iowa’s current beach and health-department advisories before swimming.
Water Quality Grade: D, Poor
Very murky, less than 3 ft of visibility. Chlorophyll-a: 22.9 µg/L. Trophic State Index: 61.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 22.9 µg/L | D |
| Trophic State Index (TSI) | 61 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 12 acres |
| Public Access | Yes |
Where to stay near Springbrook Lake
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Fishing Springbrook Lake
Water Quality Trend: → Stable
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.036 m/yr | 4 |
| Chlorophyll-a | ↓ Declining | +7.46 µg/L/yr | 4 |
Recreation & Access
Water Temperature
Springbrook Lake averages about 78°F at the surface in summer, usually warmest in Jul (about 81°F) and coldest in Sep (about 68°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 100 field readings (2010–2023) via the EPA Water Quality Portal. See the full Springbrook Lake water temperature breakdown →
Location & Depth Map
Free interactive depth-contour map of Springbrook Lake, reaching a maximum surveyed depth of 20 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
County Ranking
Ranked #1 of 1 lakes in Guthrie County
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More records, surveys & data sources
Reservoir Info (USACE NID)
Springbrook Lake is a man-made reservoir impounded by the Springbrook Lake Dam (completed 1934), built primarily for recreation on the TR-MIDDLE RACCOON RIVER; earth-type dam, 40 ft tall and 580 ft long.
- Surface area
- 12 ac
- Normal storage
- 58 ac-ft
- Max storage
- 187 ac-ft
- Drainage area
- 2.54 sq mi
- Hazard class
- Significant
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA01345 · Operator website
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Springbrook Lake under Clean Water Act (NPDES) discharge permits.
- Dnr Springbrook State Park-Campground AreaGuthrie Center · 0.3 mi away · NPDES IA0075281
- Dnr Springbrook State ParkGuthrie Center · 0.7 mi away · NPDES IA0075272
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
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