Loch Mary Reservoir
Hopkins County, Kentucky148 acresView mapDirections
Kentucky DOW publishes the water-quality measurements for Loch Mary Reservoir. Here is what has been measured.
- Mesotrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- 29 ft max depth
- Public access
- Limited data
Loch Mary Reservoir in Hopkins County, Kentucky has water-quality measurements published by Kentucky DOW, shown here as reported. Phosphorus: 22.1 µg/L. Surface area: 148 acres.
Loch Mary Reservoir is a 148-acre mesotrophic lake in Hopkins County, Kentucky with an estimated average depth of about 29 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 3 other monitored lakes in Hopkins County, Loch Mary Reservoir ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, KY DOW, last sampled 2019-09-04. Methodology: how these readings are compared.
Loch Mary Reservoir covers about 150 acres in Hopkins County. If you are planning to stay, you can search lake houses and cabins around Loch Mary Reservoir on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
Swimming conditions
Readings onlyLimited data
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. Loch Mary Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Loch Mary Reservoir 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 Loch Mary Reservoir
These are the measurements Kentucky DOW publishes for Loch Mary Reservoir, 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 22.1 µg/L. TSI 49.
| 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 | 22.1µg/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. | 49 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Loch Mary Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~29 ft est.
Surface area
148 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 Loch Mary Reservoir.
Lake Size & Watershed
Watershed (drainage) area
4 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.4 mi
HydroLAKES / HydroSHEDS
Elevation
427 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 Loch Mary Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Loch Mary Reservoir in Hopkins County, Kentucky — 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 Loch Mary Reservoir
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Fishing Loch Mary Reservoir
Water quality readings over time
2 seasons of samples on record (2016–2019). Calling a direction takes at least 4 years of the same measurement.
Phosphorus
Worsening+3.3 µg/L/yr2 years
Reservoir Info (USACE NID)
Loch Mary Reservoir is a man-made reservoir impounded by the Loch Mary Reservoir Dam (completed 1950), built primarily for water supply on the Clear Creek; earth-type dam, 27 ft tall and 1,300 ft long.
- Surface area
- 148 ac
- Normal storage
- 1,450 ac-ft
- Max storage
- 2,350 ac-ft
- Drainage area
- 3.67 sq mi
- Hazard class
- High
- Owner
- CITY OF EARLINGTON
Source: USACE National Inventory of Dams, NID ID KY00148 · Operator website
EPA Impairment Status
Loch Mary Reservoir 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-1171 · Official waterbody report
Nearby Lakes in Hopkins County
Frequently asked questions about Loch Mary Reservoir
Where is Loch Mary Reservoir?
- Loch Mary Reservoir is a lake in Hopkins County, Kentucky. Its water-quality measurements are published by Kentucky DOW and shown on this page as reported.
What is the water quality of Loch Mary Reservoir?
- Loch Mary Reservoir in Hopkins County, Kentucky has water-quality measurements published by Kentucky DOW, shown here as reported. Phosphorus: 22.1 µg/L. Surface area: 148 acres.
Is Loch Mary Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Loch Mary Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Loch Mary Reservoir?
- No published bathymetric survey covers Loch Mary Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 29 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 148 acres.
Can I fish at Loch Mary Reservoir?
- Public access to Loch Mary Reservoir 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 Loch Mary Reservoir across LakeQuality
More lakes in Kentucky
Other Lakes in Kentucky
Mesotrophic Lakes in Kentucky
Where this data comes from
12 measurements from 2 monitoring stations, 2016–2019. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- KY WQX
21KY_WQX12 samples · 2016–2019
Analytical methods
- Phosphorus by Colorimetry
- Total Phosphorus After Block Digestion
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)