Lake Nehai Tonkayea
Chariton County, Missouri250 acresView mapDirections
Missouri DNR publishes the water-quality measurements for Lake Nehai Tonkayea. Here is what has been measured.
- Oligotrophic
- 45 ft max depth
Lake Nehai Tonkayea in Chariton County, Missouri has water-quality measurements published by Missouri DNR, shown here as reported. Water clarity: 8 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 1.3 µg/L. Surface area: 250 acres.
Lake Nehai Tonkayea is a 250-acre cold, clear oligotrophic lake in Chariton County, Missouri with an estimated average depth of about 45 feet. Overall water quality is improving over recent sampling years. Compared to the 2 other monitored lakes in Chariton County, Lake Nehai Tonkayea ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2023-08-10. Methodology: how these readings are compared.
Lake Nehai Tonkayea covers about 250 acres in Chariton County. For a place on the water, look through cabin and lake-house rentals near Lake Nehai Tonkayea on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
Swimming conditions
Readings onlyLow algae
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 Lake Nehai Tonkayea 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 Lake Nehai Tonkayea
These are the measurements Missouri DNR publishes for Lake Nehai Tonkayea, 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 ft. Phosphorus 10 µg/L. Chlorophyll-a 1.3 µg/L. TSI 39.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 10µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.3µg/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. | 39 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Lake Nehai Tonkayea
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Lake Nehai Tonkayea typically sits around 83°F at the surface in August. Summer average is about 82°F. Usually warmest in Jul (about 83°F) and coldest in May (about 69°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (69°F) to its warmest (83°F).
Typical surface water temperature by month, from 19 field readings (2015–2023) via the EPA Water Quality Portal. See the full Lake Nehai Tonkayea water temperature breakdown →
Lake Details
Max depth
~45 ft est.
Surface area
250 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Missouri has not published bathymetry for Lake Nehai Tonkayea.
Lake Size & Watershed
Watershed (drainage) area
2 sq mi
HydroLAKES / HydroSHEDS
Shoreline
5.6 mi
HydroLAKES / HydroSHEDS
Elevation
751 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.
Stays via Stay22
Stays near Lake Nehai Tonkayea
Compare lakeside cabins, hotels, and vacation rentals near Lake Nehai Tonkayea in Chariton County, Missouri — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Lake Nehai Tonkayea
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Fishing Lake Nehai Tonkayea
Water quality readings over time
3 seasons of samples on record (2021–2023). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving3 years
Phosphorus
Improving-0.35 µg/L/yr3 years
Chlorophyll-a
Improving-0.4 µg/L/yr3 years
Reservoir Info (USACE NID)
Lake Nehai Tonkayea is a man-made reservoir impounded by the Nehai Tonkayea Lake Dam (completed 1970), built primarily for recreation on the TR-MUSSEL FORK; earth-type dam, 65 ft tall and 1,700 ft long.
- Surface area
- 250 ac
- Normal storage
- 5,417 ac-ft
- Max storage
- 9,100 ac-ft
- Drainage area
- 1.48 sq mi
- Hazard class
- Low
- Owner
- NEHAI TONKAYEA POA
Source: USACE National Inventory of Dams, NID ID MO10627 · Operator website
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Lake Nehai Tonkayea under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Lake Nehai Tonkayea WwtpKeytesville · 0.2 mi away · NPDES MO0088510Recent violation
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 Chariton County
Frequently asked questions about Lake Nehai Tonkayea
Where is Lake Nehai Tonkayea?
- Lake Nehai Tonkayea is a lake in Chariton County, Missouri. Its water-quality measurements are published by Missouri DNR and shown on this page as reported.
What is the water quality of Lake Nehai Tonkayea?
- Lake Nehai Tonkayea in Chariton County, Missouri has water-quality measurements published by Missouri DNR, shown here as reported. Water clarity: 8 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 1.3 µg/L. Surface area: 250 acres.
Is Lake Nehai Tonkayea 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 Lake Nehai Tonkayea?
- Lake Nehai Tonkayea typically sits around 83°F at the surface in August, from 19 EPA Water Quality Portal field readings (2015–2023). That is a typical value for the month, not a live reading.
How deep is Lake Nehai Tonkayea?
- No published bathymetric survey covers Lake Nehai Tonkayea, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 45 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 250 acres.
Explore Lake Nehai Tonkayea across LakeQuality
Depth, room, public access, and the state wake-sport rules
Species activity outlook by water temperature and season
Where to stay at Missouri's top lakes, each with its readings
Missouri's cleanest lakes, ranked on agency measurements
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Where this data comes from
55 measurements from 1 monitoring station, 2021–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Univ. of Missouri, Columbia
UMC55 samples · 2021–2023
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)
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)
Lake size & watershed from HydroLAKES (HydroSHEDS)