Mashapaug Pond
Tolland County, Connecticut273 acresView mapDirections
CT DEEP publishes the water-quality measurements for Mashapaug Pond. Here is what has been measured.
- Oligotrophic
- Public access
- Limited data
Mashapaug Pond in Tolland County, Connecticut has water-quality measurements published by CT DEEP, shown here as reported. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Surface area: 273 acres.
Mashapaug Pond is a 273-acre cold, clear oligotrophic lake in Tolland County, Connecticut. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 3 other monitored lakes in Tolland County, Mashapaug Pond ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2023-08-17. Methodology: how these readings are compared.
What Mashapaug Pond is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
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 Mashapaug Pond 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 Mashapaug Pond
These are the measurements CT DEEP publishes for Mashapaug Pond, 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 8 µg/L. Chlorophyll-a 1.6 µg/L. TSI 35.
| 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 | 8µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.6µg/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. | 35 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Mashapaug Pond
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
273 acres
Public access
Yes
Listed by CT DEEP
No bathymetric survey has been published for Mashapaug Pond, so its depth is not documented here.
Recreation & Access
- Mashapaug LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Fishing Mashapaug Pond
Reservoir Info (USACE NID)
Mashapaug Pond is a man-made reservoir impounded by the Mashapaug Pond Dam #2 West (completed 1900), built primarily for recreation on the Bigelow Brook; earth-type dam, 14 ft tall and 500 ft long.
- Surface area
- 273 ac
- Normal storage
- 5,300 ac-ft
- Max storage
- 6,725 ac-ft
- Drainage area
- 4.68 sq mi
- Hazard class
- Significant
- Owner
- Connecticut DEEP
Source: USACE National Inventory of Dams, NID ID CT00640 · Operator website
Nearby Lakes in Tolland County
Frequently asked questions about Mashapaug Pond
Where is Mashapaug Pond?
- Mashapaug Pond is a lake in Tolland County, Connecticut. Its water-quality measurements are published by CT DEEP and shown on this page as reported.
What is the water quality of Mashapaug Pond?
- Mashapaug Pond in Tolland County, Connecticut has water-quality measurements published by CT DEEP, shown here as reported. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Surface area: 273 acres.
Is Mashapaug Pond safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Are there boat ramps on Mashapaug Pond?
- Mashapaug Pond has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Mashapaug Lake. Public access is listed as yes.
Can I fish at Mashapaug Pond?
- Mashapaug Pond has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Connecticut's fish and wildlife agency, so check its current regulations before you go.
Explore Mashapaug Pond across LakeQuality
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Other Lakes in Connecticut
Oligotrophic Lakes in Connecticut
Where this data comes from
10 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- Connecticut Department Of Energy And Environmental Protection
CT_DEP01_WQX10 samples · 2023
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.
Other records on this page
Named boat-access points from the USGS National Boat Ramps inventory