Knapp Brook Lake
Windsor County, Vermont35 acresView mapDirections
Vermont DEC publishes the water-quality measurements for Knapp Brook Lake. Here is what has been measured.
- 48 ft max depth
- Public access
- Limited data
Knapp Brook Lake in Windsor County, Vermont has water-quality measurements published by Vermont DEC, shown here as reported. Water clarity: 3.6 ft visibility. Surface area: 35 acres.
Knapp Brook Lake is a 35-acre lake in Windsor County, Vermont with an estimated average depth of about 48 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, VT DEC, last sampled 2024-05-02. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Knapp Brook Lake is safe to swim in today is a call for the Vermont Department of Environmental Conservation and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Knapp Brook Lake
These are the measurements Vermont DEC publishes for Knapp Brook Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 3.6 ft. TSI 59.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| 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. | 59 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Knapp Brook Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~48 ft est.
Surface area
35 acres
Public access
Yes
Listed by Vermont DEC
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Vermont has not published bathymetry for Knapp Brook Lake.
Lake Size & Watershed
Watershed (drainage) area
3 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.7 mi
HydroLAKES / HydroSHEDS
Elevation
1,280 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.
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Fishing Knapp Brook 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
Improving3 years
Reservoir Info (USACE NID)
Knapp Brook Lake is a man-made reservoir impounded by the Knapp Brook Site No. 2 (completed 1961), built primarily for recreation on the Knapp Brook; earth-type dam, 27 ft tall and 540 ft long.
- Surface area
- 35 ac
- Normal storage
- 0 ac-ft
- Max storage
- 623 ac-ft
- Drainage area
- 2.92 sq mi
- Hazard class
- Significant
- Owner
- STATE OF VERMONT - DFW
Source: USACE National Inventory of Dams, NID ID VT00077 · Operator website · Matched by proximity (0.13 km)
Nearby Lakes in Windsor County
Frequently asked questions about Knapp Brook Lake
Where is Knapp Brook Lake?
- Knapp Brook Lake is a lake in Windsor County, Vermont. Its water-quality measurements are published by Vermont DEC and shown on this page as reported.
What is the water quality of Knapp Brook Lake?
- Knapp Brook Lake in Windsor County, Vermont has water-quality measurements published by Vermont DEC, shown here as reported. Water clarity: 3.6 ft visibility. Surface area: 35 acres.
Is Knapp Brook Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Knapp Brook Lake?
- No published bathymetric survey covers Knapp Brook Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 48 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 35 acres.
Can I fish at Knapp Brook Lake?
- Public access to Knapp Brook Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Vermont's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
40 measurements from 2 monitoring stations, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Vermont Dept of Environmental Conservation
1VTDECWQ40 samples · 2020–2024
Analytical methods
- EPA approved Alternate Test Procedure for 4500 P H. Has a 28 day hold without acid preservation.
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 2130 B ~ Nephelometric Method
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
Lake size & watershed from HydroLAKES (HydroSHEDS)