Little Sioux Park Lake
Woodbury County, IowaView mapDirections
Iowa DNR publishes the water-quality measurements for Little Sioux Park Lake. Here is what has been measured.
- Mesotrophic
Little Sioux Park Lake in Woodbury County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 5.7 ft visibility. Phosphorus: 19 µg/L. Chlorophyll-a (algae): 5.7 µg/L.
Free interactive depth-contour map of Little Sioux Park Lake, reaching a maximum surveyed depth of 28 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Little Sioux Park Lake is a mesotrophic lake in Woodbury County, Iowa. Overall water quality is declining over recent sampling years. Compared to the 2 other monitored lakes in Woodbury County, Little Sioux Park Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-03. Methodology: how these readings are compared.
Swimming conditions
Readings onlyBacteria tested: low
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.
Based on E. coli testing, Little Sioux Park Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 5 samples across 2 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.
Whether Little Sioux Park 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 Little Sioux Park Lake
These are the measurements Iowa DNR publishes for Little Sioux Park Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5.7 ft. Phosphorus 19 µg/L. Chlorophyll-a 5.7 µg/L. TSI 49.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.7ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 19µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 5.7µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 49 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Little Sioux Park Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Little Sioux Park Lake typically sits around 79°F at the surface in August. Summer average is about 79°F. Usually warmest in Jun (about 79°F) and coldest in May (about 65°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (65°F) to its warmest (79°F).
Typical surface water temperature by month, from 26 field readings (2010–2023) via the EPA Water Quality Portal. See the full Little Sioux Park Lake water temperature breakdown →
Stays via Stay22
Stays near Little Sioux Park Lake
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Fishing Little Sioux Park Lake
Water Quality Trend: Worsening
Based on 4 years of monitoring (2021–2024).
Water clarity
Worsening4 years
Phosphorus
Stable+0.15 µg/L/yr4 years
Chlorophyll-a
Worsening+0.25 µg/L/yr4 years
Regulated Pollution Sources Nearby
4 EPA-permitted facilities operate within about 5 miles of Little Sioux Park Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Correctionville City Of StpCorrectionville · 1.9 mi away · NPDES IA0023531Recent violation
- Iowa Dot Maintenance Garage-CorrectionvilleCorrectionville · 2.8 mi away · NPDES IA0076325
- Pithan Feedlots, Inc.Anthon · 4.4 mi away · NPDES IA0080683
- Anthon City Of StpAnthon · 4.5 mi away · NPDES IA0042854
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 Woodbury County
Frequently asked questions about Little Sioux Park Lake
Where is Little Sioux Park Lake?
- Little Sioux Park Lake is a lake in Woodbury County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Little Sioux Park Lake?
- Little Sioux Park Lake in Woodbury County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 5.7 ft visibility. Phosphorus: 19 µg/L. Chlorophyll-a (algae): 5.7 µg/L.
Is Little Sioux Park Lake safe to swim in?
- Based on E. coli testing, Little Sioux Park Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 5 samples across 2 seasons. That is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether Little Sioux Park Lake is safe to swim in today is a call for Iowa's water agency and the county health department; check their current beach advisories before you swim.
What is the water temperature of Little Sioux Park Lake?
- Little Sioux Park Lake typically sits around 79°F at the surface in August, from 26 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
Explore Little Sioux Park Lake across LakeQuality
More lakes in Iowa
Other Lakes in Iowa
Mesotrophic Lakes in Iowa
Where this data comes from
53 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_WQX53 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)