Loch Ayr Lake
Ringgold County, Iowa78 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Loch Ayr Lake. Here is what has been measured.
- Eutrophic
- Impaired · Turbidity
- 30 ft max depth
- Limited data
Loch Ayr Lake in Ringgold County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 2 ft visibility. Phosphorus: 69.5 µg/L. Chlorophyll-a (algae): 29.7 µg/L. Surface area: 78 acres.
Free interactive depth-contour map of Loch Ayr Lake, reaching a maximum surveyed depth of 17 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Loch Ayr Lake is a 78-acre productive, nutrient-rich eutrophic lake in Ringgold County, Iowa with an estimated average depth of about 30 feet. Overall water quality is declining over recent sampling years. Compared to the 1 other monitored lakes in Ringgold County, Loch Ayr Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2022-09-06. Methodology: how these readings are compared.
Swimming conditions
Readings onlyRecreation use not supported
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 Ayr Lake is listed impaired under Clean Water Act §303(d) (IR 5) for turbidity. Check local advisories before you swim.
Whether Loch Ayr Lake is safe to swim in today is a call for the Iowa Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Loch Ayr Lake
These are the measurements Iowa DNR publishes for Loch Ayr Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2 ft of visibility. Phosphorus 69.5 µg/L. Chlorophyll-a 29.7 µg/L. TSI 66.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 69.5µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 29.7µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 66 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Loch Ayr Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Loch Ayr Lake typically sits around 70°F at the surface in September. Summer average is about 82°F. Usually warmest in Jul (about 82°F) and coldest in May (about 68°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (68°F) to its warmest (82°F).
Typical surface water temperature by month, from 9 field readings (2018–2022) via the EPA Water Quality Portal. See the full Loch Ayr Lake water temperature breakdown →
Lake Details
Max depth
~30 ft est.
Surface area
78 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Iowa has not published bathymetry for Loch Ayr Lake.
Lake Size & Watershed
Watershed (drainage) area
4 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.9 mi
HydroLAKES / HydroSHEDS
Elevation
1,129 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 Ayr Lake
Compare lakeside cabins, hotels, and vacation rentals near Loch Ayr Lake in Ringgold County, Iowa — 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Loch Ayr Lake are listed below.
Top-rated places to stay near Loch Ayr Lake
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Fishing Loch Ayr Lake
Water quality readings over time
3 seasons of samples on record (2020–2022). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening3 years
Phosphorus
Worsening+23.75 µg/L/yr3 years
Chlorophyll-a
Worsening+6.5 µg/L/yr3 years
Reservoir Info (USACE NID)
Loch Ayr Lake is a man-made reservoir impounded by the Mount Ayr Reservoir Dam (completed 1930), built primarily for water supply on the TR-WALNUT CREEK; earth-type dam, 40 ft tall and 1,200 ft long.
- Surface area
- 78 ac
- Normal storage
- 780 ac-ft
- Max storage
- 1,410 ac-ft
- Drainage area
- 4.05 sq mi
- Hazard class
- Significant
- Owner
- City of Mounty Ayr
Source: USACE National Inventory of Dams, NID ID IA01370 · Operator website
EPA Impairment Status
Loch Ayr 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: Recreation.
Source: EPA ATTAINS assessment unit IA 05-GRA-1381 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Loch Ayr Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Mount Ayr City Of StpMount Ayr · 2.5 mi away · NPDES IA0023574Recent 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 Ringgold County
Frequently asked questions about Loch Ayr Lake
Where is Loch Ayr Lake?
- Loch Ayr Lake is a lake in Ringgold County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Loch Ayr Lake?
- Loch Ayr Lake in Ringgold County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 2 ft visibility. Phosphorus: 69.5 µg/L. Chlorophyll-a (algae): 29.7 µg/L. Surface area: 78 acres.
Is Loch Ayr Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Loch Ayr Lake is listed impaired under Clean Water Act §303(d) (IR 5) for turbidity. Check local advisories before you swim.
What is the water temperature of Loch Ayr Lake?
- Loch Ayr Lake typically sits around 70°F at the surface in September, from 9 EPA Water Quality Portal field readings (2018–2022). That is a typical value for the month, not a live reading.
How deep is Loch Ayr Lake?
- No published bathymetric survey covers Loch Ayr Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 30 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 78 acres.
Explore Loch Ayr Lake across LakeQuality
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Where this data comes from
36 measurements from 1 monitoring station, 2020–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX36 samples · 2020–2022
Analytical methods
- Unknown
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- ISU modification of APHA 2130-B
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)
Lake size & watershed from HydroLAKES (HydroSHEDS)