Lake Blackshear
Crisp County, Georgia8,700 acresView mapDirections
Georgia EPD publishes the water-quality measurements for Lake Blackshear. Here is what has been measured.
- Eutrophic
Lake Blackshear in Crisp County, Georgia has water-quality measurements published by Georgia EPD, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 30.5 µg/L. Chlorophyll-a (algae): 12.5 µg/L. Surface area: 8700 acres.
Lake Blackshear is a 8,700-acre productive, nutrient-rich eutrophic lake in Crisp County, Georgia. Overall water quality is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, Georgia EPD, last sampled 2025-10-27. Methodology: how these readings are compared.
At about 8,700 acres, Lake Blackshear is large enough that where you stay decides which shore you see most of. Vrbo is where to look for cabins and lake homes around Lake Blackshear, and Booking.com and Expedia search hotels near the lake for your dates.
What Lake Blackshear is good for
From access and monitoring records, not editorial picks.
- Big water8,700 acres
Swimming conditions
Readings onlyLow algae
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 Lake Blackshear is safe to swim in today is a call for the Georgia Environmental Protection Division and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lake Blackshear
These are the measurements Georgia EPD publishes for Lake Blackshear, 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 3.9 ft. Phosphorus 30.5 µg/L. Chlorophyll-a 12.5 µg/L. TSI 55.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 30.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 12.5µg/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. | 55 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Lake Blackshear
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
8,700 acres
No bathymetric survey has been published for Lake Blackshear, so its depth is not documented here.
Stays via Stay22
Stays near Lake Blackshear
Compare lakeside cabins, hotels, and vacation rentals near Lake Blackshear in Crisp County, Georgia — 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 Lake Blackshear
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Fishing Lake Blackshear
Water Quality Trend: Worsening
Based on 14 years of monitoring (2012–2025).
Water clarity
Stable14 years
Phosphorus
Stable-0.26 µg/L/yr6 years
Chlorophyll-a
Worsening+0.63 µg/L/yr14 years
Reservoir Info (USACE NID)
Lake Blackshear is a man-made reservoir impounded by the Crisp County (Warwick) (completed 1930), built primarily for hydroelectric on the Flint; gravity-type dam, 50 ft tall and 4,500 ft long.
- Surface area
- 8,700 ac
- Normal storage
- 145,000 ac-ft
- Max storage
- 160,000 ac-ft
- Drainage area
- 3,750 sq mi
- Hazard class
- High
- Owner
- Crisp County Power Commission
Source: USACE National Inventory of Dams, NID ID GA00719 · Operator website
Nearby Lakes in Crisp County
Frequently asked questions about Lake Blackshear
Where is Lake Blackshear?
- Lake Blackshear is a lake in Crisp County, Georgia. Its water-quality measurements are published by Georgia EPD and shown on this page as reported.
What is the water quality of Lake Blackshear?
- Lake Blackshear in Crisp County, Georgia has water-quality measurements published by Georgia EPD, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 30.5 µg/L. Chlorophyll-a (algae): 12.5 µg/L. Surface area: 8700 acres.
Is Lake Blackshear safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Lake Blackshear across LakeQuality
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Where this data comes from
260 measurements from 1 monitoring station, 2012–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Georgia DNR Environmental Protection Division
21GAEPD_WQX260 samples · 2012–2025
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- Turbidity by Nephelometry
- 2120 B ~ Color in Water by Visual Comparison
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.