Lake Tishomingo Nr. Dam is a 120-acre productive, nutrient-rich eutrophic lake in Jefferson County, Missouri. Water quality is graded C based on 3 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 6 other monitored lakes in Jefferson County, Lake Tishomingo Nr. Dam ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2024-08-13. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 5.4 ft. Phosphorus level: 23.5 µg/L. Chlorophyll-a: 7.1 µg/L. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.4 ft | D |
| Phosphorus | 23.5 µg/L | B |
| Chlorophyll-a (Algae) | 7.1 µg/L | B |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 120 acres |
Where to stay near Lake Tishomingo Nr. Dam
Compare lakeside cabins, hotels, and vacation rentals near Lake Tishomingo Nr. Dam in Jefferson 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.
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Fishing Lake Tishomingo Nr. Dam
Water Quality Trend: ↑ Improving
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +1.54 m/yr | 2 |
| Phosphorus | ↑ Improving | -6.85 µg/L/yr | 3 |
| Chlorophyll-a | ↑ Improving | -3.65 µg/L/yr | 3 |
Water Temperature
Lake Tishomingo Nr. Dam averages about 83°F at the surface in summer, usually warmest in Jul (about 84°F) and coldest in Apr (about 64°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 31 field readings (2010–2024) via the EPA Water Quality Portal. See the full Lake Tishomingo Nr. Dam water temperature breakdown →
Location
County Ranking
Ranked #5 of 7 lakes in Jefferson County
Cleaner Lakes Within 30 Miles
Lake Tishomingo Nr. Dam holds Grade C. 2 nearby lakes hold higher grades.
- ALake Wauwanoka Nr. DamJefferson County · 7.2 mi · Two grade letters higher (C → A)
- BMarion ReservoirFranklin County · 9.1 mi · Higher grade (C → B)
Nearby Lakes in Jefferson County
Explore Lake Tishomingo Nr. Dam across LakeGrade
More Missouri Lake Rankings
Other Grade C Lakes in Missouri
Eutrophic Lakes in Missouri
More records, surveys & data sources
Reservoir Info (USACE NID)
Lake Tishomingo Nr. Dam is a man-made reservoir impounded by the Lake Tishomingo Dam (completed 1950), built primarily for recreation on the TRIBUTARY TO BELEW CREEK; earth-type dam, 68 ft tall and 870 ft long.
- Surface area
- 120 ac
- Normal storage
- 2,376 ac-ft
- Max storage
- 3,128 ac-ft
- Drainage area
- 2.97 sq mi
- Hazard class
- High
- Owner
- LAKE TISHOMINGO POA
Source: USACE National Inventory of Dams, NID ID MO30039 · Operator website · Matched by proximity (0.14 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
16 EPA-permitted facilities operate within about 5 miles of Lake Tishomingo Nr. Dam under Clean Water Act (NPDES) discharge permits. 15 facilities have a reported Clean Water Act violation in the past three years.
- Lake Tishomingo WwtpHillsboro · 0.1 mi away · NPDES MO0136298Recent violation
- Jcpsd Wedgewood Village WwtpCedar Hill · 1.6 mi away · NPDES MO0105970Recent violation
- Fisher Commercial Area WwtfHillsboro · 1.8 mi away · NPDES MO0086932Recent violation
- Country Life Acres Subdivision WwtfCedar Hill · 2 mi away · NPDES MO0090905Recent violation
- Jcpsd, Sennawood Village WwtpCedar Hill · 2.1 mi away · NPDES MO0106577Recent violation
- Jcpsd, Bel Air Estates WwtpCedar Hill · 2.2 mi away · NPDES MO0086576Recent 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.
Data Sources
Water quality data from the EPA Water Quality Portal
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-08-13
Monitoring stations: 1