Little Prairie Lake
Phelps County, Missouri100 acresView mapDirections
Missouri DNR publishes the water-quality measurements for Little Prairie Lake. Here is what has been measured.
- Impaired · Mercury
- Limited data
Little Prairie Lake in Phelps County, Missouri has water-quality measurements published by Missouri DNR, shown here as reported. Water clarity: 8.6 ft visibility. Phosphorus: 54 µg/L. Chlorophyll-a (algae): 8.9 µg/L. Surface area: 100 acres.
Little Prairie Lake is a 100-acre lake in Phelps County, Missouri. Water clarity is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2021-09-07. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Little Prairie Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Little Prairie Lake is safe to swim in today is a call for the Missouri Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Little Prairie Lake
These are the measurements Missouri DNR publishes for Little Prairie Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 8.6 ft. Phosphorus 54 µg/L. Chlorophyll-a 8.9 µg/L. TSI 53.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 54µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 8.9µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 53 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Little Prairie Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Little Prairie Lake typically sits around 82°F at the surface in August. Summer average is about 83°F. Usually warmest in Jul (about 86°F) and coldest in Jun (about 82°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (82°F) to its warmest (86°F).
Typical surface water temperature by month, from 10 field readings (2016–2021) via the EPA Water Quality Portal. See the full Little Prairie Lake water temperature breakdown →
Lake Details
Surface area
100 acres
No bathymetric survey has been published for Little Prairie Lake, so its depth is not documented here.
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Fishing Little Prairie Lake
Water Quality Trend: Stable
Based on 5 years of monitoring (2020–2024).
Water clarity
Worsening4 years
Phosphorus
Stable-0.19 µg/L/yr5 years
Chlorophyll-a
Improving-2.03 µg/L/yr5 years
Reservoir Info (USACE NID)
Little Prairie Lake is a man-made reservoir impounded by the William E. Towell Dam (completed 1965), built primarily for recreation on the TRIBUTARY OF BOUBEUSE RIVER; earth-type dam, 48 ft tall and 1,450 ft long.
- Surface area
- 100 ac
- Normal storage
- 1,300 ac-ft
- Max storage
- 2,490 ac-ft
- Drainage area
- 2.41 sq mi
- Hazard class
- High
- Owner
- MO DEPT OF CONSERVATION
Source: USACE National Inventory of Dams, NID ID MO30090 · Operator website · Matched by proximity (0.39 km)
EPA Impairment Status
Little Prairie Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Fish consumption.
Source: EPA ATTAINS assessment unit MO_7287.00 · Official waterbody report
Regulated Pollution Sources Nearby
10 EPA-permitted facilities operate within about 5 miles of Little Prairie Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Glado Wastewater Treatment FacilityRolla · 1.5 mi away · NPDES MO0084191Recent violation
- Formerly Little Dixie Truck Port WwtfRolla · 1.7 mi away · NPDES MO0104493Recent violation
- Country Valley HomeSt. James · 2.7 mi away · NPDES MO0088064Recent violation
- Brewer Science, IncRolla · 1.6 mi away · NPDES MONX00017
- Brewer Science, Inc. - Building 3A/8Rolla · 1.7 mi away · NPDES MONX00995
- Mo-Sci CorporationRolla · 1.7 mi away · NPDES MONX00306
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 Phelps County
Frequently asked questions about Little Prairie Lake
Where is Little Prairie Lake?
- Little Prairie Lake is a lake in Phelps County, Missouri. Its water-quality measurements are published by Missouri DNR and shown on this page as reported.
What is the water quality of Little Prairie Lake?
- Little Prairie Lake in Phelps County, Missouri has water-quality measurements published by Missouri DNR, shown here as reported. Water clarity: 8.6 ft visibility. Phosphorus: 54 µg/L. Chlorophyll-a (algae): 8.9 µg/L. Surface area: 100 acres.
Is Little Prairie Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Little Prairie Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
What is the water temperature of Little Prairie Lake?
- Little Prairie Lake typically sits around 82°F at the surface in August, from 10 EPA Water Quality Portal field readings (2016–2021). That is a typical value for the month, not a live reading.
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Where this data comes from
4 measurements from 1 monitoring station, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Missouri Dept. of Natural Resources
MDNR4 samples · 2021
Analytical methods
- Depth, Secchi disk in meters
- Nitrogen and Phosphorus, Total, Whole-water, Alkaline Persulfate Digest
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)