Alexander Lake
Windham County, Connecticut31 acresView mapDirections
CT DEEP publishes the water-quality measurements for Alexander Lake. Here is what has been measured.
- Mesotrophic
- Limited data
Alexander Lake in Windham County, Connecticut has water-quality measurements published by CT DEEP, shown here as reported. Phosphorus: 27 µg/L. Chlorophyll-a (algae): 0.9 µg/L. Surface area: 31 acres.
Alexander Lake is a 31-acre mesotrophic lake in Windham County, Connecticut. Compared to the 2 other monitored lakes in Windham County, Alexander Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2024-08-28. Methodology: how these readings are compared.
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. Check local advisories before you swim.
Whether Alexander Lake is safe to swim in today is a call for the Connecticut Department of Energy and Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Alexander Lake
These are the measurements CT DEEP publishes for Alexander 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 27 µg/L. Chlorophyll-a 0.9 µg/L. TSI 41.
| 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 | 27µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 0.9µg/L | Measured, not scored 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. | 41 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Alexander Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
31 acres
No bathymetric survey has been published for Alexander Lake, so its depth is not documented here.
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Fishing Alexander Lake
Reservoir Info (USACE NID)
Alexander Lake is a man-made reservoir impounded by the Dayville Dike (completed 1925), built primarily for hydroelectric on the Five Mile River; earth-type dam, 14 ft tall and 5,000 ft long.
- Surface area
- 31 ac
- Normal storage
- 93 ac-ft
- Max storage
- 93 ac-ft
- Drainage area
- 57 sq mi
- Hazard class
- Low
- Owner
- Summit Hydro, LLC
Source: USACE National Inventory of Dams, NID ID CT00169 · Operator website · Matched by proximity (0.94 km)
Nearby Lakes in Windham County
Frequently asked questions about Alexander Lake
Where is Alexander Lake?
- Alexander Lake is a lake in Windham County, Connecticut. Its water-quality measurements are published by CT DEEP and shown on this page as reported.
What is the water quality of Alexander Lake?
- Alexander Lake in Windham County, Connecticut has water-quality measurements published by CT DEEP, shown here as reported. Phosphorus: 27 µg/L. Chlorophyll-a (algae): 0.9 µg/L. Surface area: 31 acres.
Is Alexander Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Alexander Lake across LakeQuality
More lakes in Connecticut
Other Lakes in Connecticut
Mesotrophic Lakes in Connecticut
Where this data comes from
26 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- Connecticut Department Of Energy And Environmental Protection
CT_DEP01_WQX26 samples · 2024
Analytical methods
- Total Phosphorus After Block Digestion
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- Nitrate-Nitrite Nitrogen by Colorimetry
- Turbidity by Nephelometry
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.