Lyford Pond-Deep Spot
Lyford Pond-Deep Spot in Merrimack County, New Hampshire has a water quality grade of C (Fair). Phosphorus: 18 µg/L. Surface area: 24.2 acres.
- Area
- 24 acres
- Type
- Mesotrophic
Lyford Pond-Deep Spot is a 24-acre mesotrophic lake in Merrimack County, New Hampshire. Water quality is graded C based on 1 sampling years through 2025. Compared to the 40 other monitored lakes in Merrimack County, Lyford Pond-Deep Spot ranks #37 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-09-07. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyModerate
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
No clarity data. Phosphorus level: 18 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 18 µg/L | Fair |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Lyford Pond-Deep Spot
Compare lakeside cabins, hotels, and vacation rentals near Lyford Pond-Deep Spot in Merrimack 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.
Top-rated places to stay near Lyford Pond-Deep Spot
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 24 acres |
No bathymetric survey has been published for Lyford Pond-Deep Spot, so its depth is not documented here.
Fishing Lyford Pond-Deep Spot
Reservoir Info (USACE NID)
Lyford Pond-Deep Spot is a man-made reservoir impounded by the Lyford Pond Dam (completed 1840), built primarily for recreation on the Guess Brook; earth-type dam, 15 ft tall and 250 ft long.
- Surface area
- 24.2 ac
- Normal storage
- 109 ac-ft
- Max storage
- 146 ac-ft
- Drainage area
- 0.28 sq mi
- Hazard class
- Significant
- Owner
- CANTERBURY SHAKER VILLAGE INC
Source: USACE National Inventory of Dams, NID ID NH00331 · Operator website · Matched by proximity (0.28 km)
EPA Impairment Status
Lyford Pond-Deep Spot is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK700060201-02 · Official waterbody report · Matched by proximity (0.05 km)
County Ranking
Ranked #37 of 41 lakes in Merrimack County
Nearby Lakes in Merrimack County
Frequently asked questions about Lyford Pond-Deep Spot
Where is Lyford Pond-Deep Spot?
- Lyford Pond-Deep Spot is a lake in Merrimack County, New Hampshire. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lyford Pond-Deep Spot?
- Lyford Pond-Deep Spot in Merrimack County, New Hampshire has a water quality grade of C (Fair). Phosphorus: 18 µg/L. Surface area: 24.2 acres.
Is Lyford Pond-Deep Spot safe to swim in?
- Generally safe for swimming, moderate water quality. Lyford Pond-Deep Spot has a water quality grade of C (Fair). Always check local health department advisories before swimming.
Explore Lyford Pond-Deep Spot across LakeGrade
More New Hampshire Lake Rankings
Top 25 by overall water quality score
Top 25 by Secchi water clarity
Grade A/B + low algae filter
Panfish-rich, public access
Full state directory
Other Grade C Lakes in New Hampshire
Mesotrophic Lakes in New Hampshire
Where this data comes from
15 measurements from 1 monitoring station, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- New Hampshire Department Of Environmental Services (BEACH)
1111330015 samples · 2022–2025
Analytical methods
- 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
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
Impairment status from EPA ATTAINS 303(d) database