Where is Lake Monomonac-Coot Bay?

Lake Monomonac-Coot Bay is a lake in Cheshire County, New Hampshire. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.

Is Lake Monomonac-Coot Bay safe to swim in?

Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Lake Monomonac-Coot Bay has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.

Lake Monomonac-Coot Bay

Grade D — Nutrient-rich

Nutrient-rich · #38 of 38 lakes in the county · Eutrophic · 18 acres

Limited DataEutrophic

Lake Monomonac-Coot Bay in Cheshire County, New Hampshire has a water quality grade of D (Nutrient-rich). Phosphorus: 40.3 µg/L. Surface area: 18 acres.

Area: 18 acres
Type: Eutrophic

Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Lake Monomonac-Coot Bay →

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Lake Monomonac-Coot Bay is a 18-acre productive, nutrient-rich eutrophic lake in Cheshire County, New Hampshire. Water quality is graded D based on 1 sampling years through 2025. Compared to the 37 other monitored lakes in Cheshire County, Lake Monomonac-Coot Bay ranks #38 for water quality.

Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-07-15. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Limited 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.

Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum

Compare the safest swimming lakes near Albany →

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Water Quality Grade: D (Nutrient-rich)

No clarity data. Phosphorus level: 40.3 µg/L. Trophic State Index: 57.

Metric	Value	Grade
Water Clarity (Secchi Depth)	No recent samples
Phosphorus	40.3 µg/L	Poor
Chlorophyll-a (Algae)	No recent samples
Trophic State Index (TSI)	57	Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Lake Monomonac-Coot Bay

Compare lakeside cabins, hotels, and vacation rentals near Lake Monomonac-Coot Bay in Cheshire County, New Hampshire — 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 grade measures nutrients and algae, not lodging — cabins and rentals around Lake Monomonac-Coot Bay are listed below.

Top-rated places to stay near Lake Monomonac-Coot Bay

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Lake Details

Characteristic	Value
Surface Area	18 acres

No bathymetric survey has been published for Lake Monomonac-Coot Bay, so its depth is not documented here.

Fishing Lake Monomonac-Coot Bay

→ Lake Monomonac-Coot Bay fishing regulations (limits, seasons, special rules)

Reservoir Info (USACE NID)

Lake Monomonac-Coot Bay is a man-made reservoir impounded by the Van Dyke Dam (completed 1982), built primarily for recreation on the Monomonac Brook; earth-type dam, 8 ft tall and 94 ft long.

Surface area: 18 ac
Normal storage: 39 ac-ft
Max storage: 66 ac-ft
Drainage area: 2.76 sq mi
Hazard class: Low
Owner: MS KATHLEEN VANDYKE EXECUTOR

Source: USACE National Inventory of Dams, NID ID NH00853 · Operator website · Matched by proximity (0.36 km)

EPA Impairment Status

Lake Monomonac-Coot Bay is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Mercury

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit NHIMP802020103-04 · Official waterbody report · Matched by proximity (0.74 km)

County Ranking

Ranked #38 of 38 lakes in Cheshire County

Nearby Lakes in Cheshire County

BLake Monomonac-Loon BayOligotrophicView →NREmerson Pond-Wozniak BeachView →NRPecker Pond-Deep SpotView →NREmerson Pond-Cathedral BeachView →BEmerson Pond-Deep SpotMesotrophicView →NRContoocook Lake-South EndView →

Frequently asked questions about Lake Monomonac-Coot Bay

Where is Lake Monomonac-Coot Bay?: Lake Monomonac-Coot Bay is a lake in Cheshire County, New Hampshire. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lake Monomonac-Coot Bay?: Lake Monomonac-Coot Bay in Cheshire County, New Hampshire has a water quality grade of D (Nutrient-rich). Phosphorus: 40.3 µg/L. Surface area: 18 acres.
Is Lake Monomonac-Coot Bay safe to swim in?: Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Lake Monomonac-Coot Bay has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.

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