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LakeQuality

Warren County, Missouri · 38.67°N · Water Quality Report Card

Sherwood Lake

A
Grade AExcellent
Mesotrophic

Sherwood Lake in Warren County, Missouri has a water quality grade of A (Excellent). Water clarity: 4.9 ft visibility. Phosphorus: 17.8 µg/L. Chlorophyll-a (algae): 4.3 µg/L.

Clarity
4.9 ft
Mean depth
~23 ft est.
Type
Mesotrophic
Trend
Declining

Sherwood Lake is a mesotrophic lake in Warren County, Missouri with an estimated average depth of about 23 feet. Water quality is graded A based on 2 sampling years through 2024. Overall water quality is declining over recent sampling years. Compared to the 15 other monitored lakes in Warren County, Sherwood Lake ranks #6 for water quality.

Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2024-09-14. Grade methodology: LakeGrade methodology.

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Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

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Water Quality Grade: A (Excellent)

Murky, only visible to about 4.9 ft. Phosphorus level: 17.8 µg/L. Chlorophyll-a: 4.3 µg/L. Trophic State Index: 48.

MetricValueGrade
Water Clarity (Secchi Depth)4.9 ft
Phosphorus17.8 µg/LGood
Chlorophyll-a (Algae)4.3 µg/LGood
Trophic State Index (TSI)48Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Average Depth~23 ft est.

Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Missouri has not published bathymetry for Sherwood Lake.

Where to stay near Sherwood Lake

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Fishing Sherwood Lake

Water Quality Trend: Declining

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.062 m/yr5
Phosphorus Declining+6.52 µg/L/yr5
Chlorophyll-a Improving-0.46 µg/L/yr5
See year-by-year chart →

Location

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County Ranking

Ranked #6 of 16 lakes in Warren County

Nearby Lakes in Warren County

More records, surveys & data sources

Lake Size & Watershed

Watershed (drainage) area
5 sq mi
Surface area
131 acres
Mean depth (modeled estimate)
~23 ft est.
Shoreline
3.2 mi
Elevation
610 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.

Where this data comes from

114 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Univ. of Missouri, ColumbiaUMC114 samples · 2020–2024

Analytical methods

  • Depth, Secchi disk in meters
  • 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
  • 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
Monitoring station identifiers (1)

Grade thresholds come from the U.S. EPA National Lakes Assessment 2022 Technical Support Document (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated.

Data Sources

Water quality data from the EPA Water Quality Portal

Lake size & watershed from HydroLAKES (HydroSHEDS)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion

Most recent sample: 2024-09-14

Monitoring stations: 1

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