Calderwood Lake
Blount County, Tennessee570 acresView mapDirections
Nutrients and algae sit mid-range for this region.
↓ down from A at the last regrade
- Mesotrophic
- Impaired · Hydrologic alteration
- #1 of 1 in the county
- 47 ft max depth
- Public access
- Limited data
Calderwood Lake in Blount County, Tennessee has a water quality grade of C (Fair). Water clarity: 16.4 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Surface area: 570 acres.
- Clarity
- 16.4 ft
- Max depth
- ~47 ft est.
- Area
- 570 acres
- Type
- Mesotrophic
- Phosphorus
- 30 µg/L
- Chlorophyll-a
- 2.4 µg/L
- Trend
- ↓ Declining
- Public access
- Yes
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Watch Calderwood Lake’s letter
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Calderwood Lake is a 570-acre mesotrophic lake in Blount County, Tennessee with an estimated average depth of about 47 feet. Water quality is graded C based on 2 sampling years through 2024. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, TDEC, last sampled 2024-11-05. Grade methodology: LakeQuality methodology.
What Calderwood Lake is good for
From access and monitoring records, not editorial picks.
- Clear water16.4 ft of visibility
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.
The C is nutrients and algae, not a swimming clearance. Calderwood Lake is listed impaired under Clean Water Act §303(d) (IR 4C) for hydrologic alteration. Check local advisories before you swim.
Water Quality Grade: C (Fair)
Crystal clear, you can see 16.4 ft down. Phosphorus 30 µg/L. Chlorophyll-a 2.4 µg/L. TSI 43. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16.4 ft | Not graded |
| Phosphorus | 30 µg/L | Fair |
| Chlorophyll-a (Algae) | 2.4 µg/L | Good |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~47 ft est. |
| Surface Area | 570 acres |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Tennessee has not published bathymetry for Calderwood Lake.
Lake Size & Watershed
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.
Fishing Calderwood Lake
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Chlorophyll-a | ↓ Declining | +0.08 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Calderwood Lake is a man-made reservoir impounded by the Calderwood (completed 1930), built primarily for hydroelectric on the Little Tennessee; arch-type dam, 230 ft tall and 916 ft long.
- Surface area
- 570 ac
- Normal storage
- 41,100 ac-ft
- Max storage
- 43,500 ac-ft
- Drainage area
- 1,856 sq mi
- Hazard class
- High
- Owner
- Brookfield Renewable Energy Group (ARO)
Source: USACE National Inventory of Dams, NID ID TN00906 · Operator website
EPA Impairment Status
Calderwood Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4C).
Causes of impairment
Source: EPA ATTAINS assessment unit TN06010204020_1000 · Official waterbody report · Matched by proximity (0.67 km)
County Ranking
Ranked #1 of 1 lakes in Blount County
Nearby Lakes in Blount County
Frequently asked questions about Calderwood Lake
Where is Calderwood Lake?
- Calderwood Lake is a lake in Blount County, Tennessee. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Calderwood Lake?
- Calderwood Lake in Blount County, Tennessee has a water quality grade of C (Fair). Water clarity: 16.4 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Surface area: 570 acres.
Is Calderwood Lake safe to swim in?
- The C is nutrients and algae, not a swimming clearance. Calderwood Lake is listed impaired under Clean Water Act §303(d) (IR 4C) for hydrologic alteration. Check local advisories before you swim.
How deep is Calderwood Lake?
- No published bathymetric survey covers Calderwood Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 47 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 570 acres.
Explore Calderwood Lake across LakeQuality
2 documented falls within 16.2 mi, nearest Abrams Falls
Species activity outlook by water temperature and season
Where to stay at Tennessee's top lakes, each with its grade
Moderate nutrients, good water quality
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Planning a trip around Great Smoky Mountains?
Calderwood Lake is about 27 miles from Great Smoky Mountains National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Great Smoky Mountains →More Tennessee Lake Rankings
Other Grade C Lakes in Tennessee
Mesotrophic Lakes in Tennessee
Where this data comes from
26 measurements from 1 monitoring station, 2014–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Carolina Dept of Environmental Quality NCDEQ-DWR WQX
21NC03WQ26 samples · 2014–2024
Analytical methods
- WSSSOP
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 2130 B ~ Nephelometric Method
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
Lake size & watershed from HydroLAKES (HydroSHEDS)