Mashapaug Pond
Mashapaug Pond in Tolland County, Connecticut has a water quality grade of B (Good). Phosphorus: 8 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Surface area: 273 acres.
- Area
- 273 acres
- Type
- Oligotrophic
- Public access
- Yes
Mashapaug Pond is a 273-acre cold, clear oligotrophic lake in Tolland County, Connecticut. Water quality is graded B based on 2 sampling years through 2023. 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. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
No clarity data. Phosphorus level: 8 µg/L. Chlorophyll-a: 1.6 µg/L. Trophic State Index: 35.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 8 µg/L | Good |
| Chlorophyll-a (Algae) | 1.6 µg/L | Not graded |
| Trophic State Index (TSI) | 35 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Mashapaug Pond
Compare lakeside cabins, hotels, and vacation rentals near Mashapaug Pond in Tolland County, Connecticut — 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.
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 273 acres |
| Public Access | Yes |
No bathymetric survey has been published for Mashapaug Pond, so its depth is not documented here.
Recreation & Access
- Mashapaug LakePublic
Named access points from the USGS National Boat Ramps inventory, snapped within 5 km. More lakes with boat ramps
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
County Ranking
Ranked #3 of 4 lakes in Tolland County
Nearby Lakes in Tolland County
Frequently asked questions about Mashapaug Pond
Where is Mashapaug Pond?
- Mashapaug Pond is a lake in Tolland County, Connecticut. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Mashapaug Pond?
- Mashapaug Pond in Tolland County, Connecticut has a water quality grade of B (Good). Phosphorus: 8 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Surface area: 273 acres.
Is Mashapaug Pond safe to swim in?
- Good for swimming, clear water with low algae levels. Mashapaug Pond has a water quality grade of B (Good). Algae concentration (chlorophyll-a) is 1.6 µg/L. Always check local health department advisories before swimming.
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.
Explore Mashapaug Pond across LakeGrade
More Connecticut Lake Rankings
Other Grade B 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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Named boat-access points from the USGS National Boat Ramps inventory