Asu Lake
Watauga County, North Carolina22 acresView mapDirections
NC DEQ publishes the water-quality measurements for Asu Lake. Here is what has been measured.
- Mesotrophic
- Limited data
Asu Lake in Watauga County, North Carolina has water-quality measurements published by NC DEQ, shown here as reported. Water clarity: 12.3 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 5.2 µg/L. Surface area: 22 acres.
Asu Lake is a 22-acre mesotrophic lake in Watauga County, North Carolina. Compared to the 2 other monitored lakes in Watauga County, Asu Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, NCDEQ, last sampled 2023-09-11. Methodology: how these readings are compared.
What Asu Lake is good for
From access and monitoring records, not editorial picks.
- Clear water12.3 ft of visibility
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Asu Lake is safe to swim in today is a call for the North Carolina Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Asu Lake
These are the measurements NC DEQ publishes for Asu Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 12.3 ft. Phosphorus 30 µg/L. Chlorophyll-a 5.2 µg/L. TSI 47.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 12.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 30µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 5.2µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 47 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Asu Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
22 acres
No bathymetric survey has been published for Asu Lake, so its depth is not documented here.
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Stays near Asu Lake
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Fishing Asu Lake
Reservoir Info (USACE NID)
Asu Lake is a man-made reservoir impounded by the Asu-Norris Branch Dam (completed 1974), built primarily for water supply on the Norris Branch; earth-type dam, 112 ft tall and 480 ft long.
- Surface area
- 22 ac
- Normal storage
- 564 ac-ft
- Max storage
- 762 ac-ft
- Drainage area
- 0.34 sq mi
- Hazard class
- High
- Owner
- Appalachian State University
Source: USACE National Inventory of Dams, NID ID NC01524 · Operator website · Matched by proximity (0.08 km)
Nearby Lakes in Watauga County
Frequently asked questions about Asu Lake
Where is Asu Lake?
- Asu Lake is a lake in Watauga County, North Carolina. Its water-quality measurements are published by NC DEQ and shown on this page as reported.
What is the water quality of Asu Lake?
- Asu Lake in Watauga County, North Carolina has water-quality measurements published by NC DEQ, shown here as reported. Water clarity: 12.3 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 5.2 µg/L. Surface area: 22 acres.
Is Asu Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Asu Lake across LakeQuality
2 documented falls within 24.6 mi, nearest Elk River Falls
Species activity outlook by water temperature and season
Where to stay at North Carolina's top lakes, each with its readings
North Carolina's cleanest lakes, ranked on agency measurements
More lakes in North Carolina
Other Lakes in North Carolina
Mesotrophic Lakes in North Carolina
Where this data comes from
20 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Carolina Dept of Environmental Quality NCDEQ-DWR WQX
21NC03WQ20 samples · 2023
Analytical methods
- WSSSOP
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 2130 B ~ Nephelometric Method
Monitoring station identifiers (1)
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.