Cap Mauzy Lake
Union County, Kentucky83 acresView mapDirections
Kentucky DOW publishes the water-quality measurements for Cap Mauzy Lake. Here is what has been measured.
- Eutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- 40 ft max depth
- Public access
Cap Mauzy Lake in Union County, Kentucky has water-quality measurements published by Kentucky DOW, shown here as reported. Phosphorus: 30 µg/L. Surface area: 83.2 acres.
Cap Mauzy Lake is a 83-acre productive, nutrient-rich eutrophic lake in Union County, Kentucky with an estimated average depth of about 40 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 1 other monitored lakes in Union County, Cap Mauzy Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, KY DOW, last sampled 2021-09-16. Methodology: how these readings are compared.
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. Cap Mauzy Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Cap Mauzy Lake is safe to swim in today is a call for the Kentucky Division of Water and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Cap Mauzy Lake
These are the measurements Kentucky DOW publishes for Cap Mauzy Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 30 µg/L. TSI 53.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 30µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading 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 Cap Mauzy Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~40 ft est.
Surface area
83 acres
Public access
Yes
Listed by Kentucky DOW
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Kentucky has not published bathymetry for Cap Mauzy Lake.
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.9 mi
HydroLAKES / HydroSHEDS
Elevation
459 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.
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Stays near Cap Mauzy Lake
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Fishing Cap Mauzy Lake
Water quality readings over time
2 seasons of samples on record (2016–2021). Calling a direction takes at least 4 years of the same measurement.
Phosphorus
Worsening+2.64 µg/L/yr2 years
Reservoir Info (USACE NID)
Cap Mauzy Lake is a man-made reservoir impounded by the Des Islet Dam (completed 1945), built primarily for recreation on the Highland Creek; earth-type dam, 32 ft tall and 900 ft long.
- Surface area
- 83.2 ac
- Normal storage
- 670.9 ac-ft
- Max storage
- 1,300 ac-ft
- Drainage area
- 1.08 sq mi
- Hazard class
- Significant
- Owner
- COMMONWEALTH OF KENTUCKY
Source: USACE National Inventory of Dams, NID ID KY00001 · Operator website · Matched by proximity (0.37 km)
EPA Impairment Status
Cap Mauzy Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life.
Source: EPA ATTAINS assessment unit KY-434 · Official waterbody report
Nearby Lakes in Union County
Frequently asked questions about Cap Mauzy Lake
Where is Cap Mauzy Lake?
- Cap Mauzy Lake is a lake in Union County, Kentucky. Its water-quality measurements are published by Kentucky DOW and shown on this page as reported.
What is the water quality of Cap Mauzy Lake?
- Cap Mauzy Lake in Union County, Kentucky has water-quality measurements published by Kentucky DOW, shown here as reported. Phosphorus: 30 µg/L. Surface area: 83.2 acres.
Is Cap Mauzy Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Cap Mauzy Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Cap Mauzy Lake?
- No published bathymetric survey covers Cap Mauzy Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 40 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 83.2 acres.
Can I fish at Cap Mauzy Lake?
- Public access to Cap Mauzy Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Kentucky's fish and wildlife agency, so check its current regulations before you go.
Explore Cap Mauzy Lake across LakeQuality
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Where this data comes from
18 measurements from 2 monitoring stations, 2016–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- KY WQX
21KY_WQX18 samples · 2016–2021
Analytical methods
- Phosphorus by Colorimetry
- Total Phosphorus After Block Digestion
- Turbidity by Nephelometry
Monitoring station identifiers (2)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)