Green Belt Lake
Black Hawk County, IowaView mapDirections
Iowa DNR publishes the water-quality measurements for Green Belt Lake. Here is what has been measured.
- Eutrophic
Green Belt Lake in Black Hawk County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 2.4 ft visibility. Phosphorus: 57 µg/L. Chlorophyll-a (algae): 18.6 µg/L.
Free interactive depth-contour map of Green Belt Lake, reaching a maximum surveyed depth of 18 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Green Belt Lake is a productive, nutrient-rich eutrophic lake in Black Hawk County, Iowa. Water clarity is improving over recent sampling years. Compared to the 6 other monitored lakes in Black Hawk County, Green Belt Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-10-28. Methodology: how these readings are compared.
Swimming conditions
Readings onlyAlgae risk
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Green Belt Lake is safe to swim in today is a call for the Iowa Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Green Belt Lake
These are the measurements Iowa DNR publishes for Green Belt Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2.4 ft of visibility. Phosphorus 57 µg/L. Chlorophyll-a 18.6 µg/L. TSI 62.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 57µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 18.6µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 62 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Green Belt Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Green Belt Lake typically sits around 75°F at the surface in September. Summer average is about 79°F. Usually warmest in Jul (about 81°F) and coldest in Sep (about 75°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (75°F) to its warmest (81°F).
Typical surface water temperature by month, from 32 field readings (2010–2023) via the EPA Water Quality Portal. See the full Green Belt Lake water temperature breakdown →
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Stays near Green Belt Lake
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Fishing Green Belt Lake
Water Quality Trend: Stable
Based on 4 years of monitoring (2021–2024).
Water clarity
Improving4 years
Phosphorus
Stable-0.4 µg/L/yr4 years
Chlorophyll-a
Worsening+8.71 µg/L/yr4 years
Regulated Pollution Sources Nearby
4 EPA-permitted facilities operate within about 5 miles of Green Belt Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- John Deere Waterloo Works (Drive Train Operations)Waterloo · 2.5 mi away · NPDES IA0000060Major
- John Deere Product Engineering CenterCedar Falls · 1.4 mi away · NPDES IA0062481Recent violation
- John Deere Foundry WaterlooWaterloo · 2.3 mi away · NPDES IA0069485
- Magellan Pipeline Company, L.P.Waterloo · 3.3 mi away · NPDES IA0072672
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.
Nearby Lakes in Black Hawk County
Frequently asked questions about Green Belt Lake
Where is Green Belt Lake?
- Green Belt Lake is a lake in Black Hawk County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Green Belt Lake?
- Green Belt Lake in Black Hawk County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 2.4 ft visibility. Phosphorus: 57 µg/L. Chlorophyll-a (algae): 18.6 µg/L.
Is Green Belt Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Green Belt Lake?
- Green Belt Lake typically sits around 75°F at the surface in September, from 32 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
Explore Green Belt Lake across LakeQuality
More lakes in Iowa
Other Lakes in Iowa
Eutrophic Lakes in Iowa
Where this data comes from
70 measurements from 1 monitoring station, 2021–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX70 samples · 2021–2024
Analytical methods
- Unknown
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- In-Vitro Determination of Chlorophyll
- ISU modification of APHA 2130-B
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Regulated discharger data from EPA ECHO (ICIS-NPDES)