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Current Conditions Yearly Table View

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2021 Chesapeake Bay Mainstem - Bottom Dissolved Oxygen (mg/L)

Click on hyperlinked stations to view charts of water quality trends.

Stations Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CB1.0 - Susquehanna River 12.7 13.5 13.3 11.7 10.8 8.5
CB1.1 - Susquehanna River 13.6 13.7 - 11.5 10.8 6.65
CB2.1 - Turkey Point 13.1 13.7 12.3 11.7 9.4 7.65
CB2.2 - Still Pond 11.7 12.8 8.6 8.2 6.5 6.3
CB3.1 - Gunpowder Neck 9.9 10.8 6.2 6 1.9 1.7
CB3.2 - Swan Point 9.2 10 6.2 5.5 1.3 0.83
CB3.3W - Bay Bridge (NW) - 6.9 8.1 4.1
CB3.3E - Bay Bridge (NE) - 8.9 6.3 5.45
CB3.3C - Bay Bridge 9.3 10 9.4 6.1 0.66 0.36
CB4.1C - Kent Point (SW) 9.7 10.3 9.5 6.2 0.84 0.6
CB4.1E - Kent Point (S) - 6.3 1 0.55
CB4.1W - Horseshoe Point - 8.3 9.2 4.7
CB4.2E - Tilghman Island - 9.9 7.8 4.7
CB4.2C - MD Mid Bay 9.9 10.3 9.7 6.3 1.8 0.9
CB4.2W - Plum Point - 10.6 9.6 5.45
CB4.3W - Dares Beach - 11.4 9.7 4.55
CB4.3E - Mouth of Choptank River - 7 3.2 0.94
CB4.3C - Dares Beach 9.8 10.4 9.9 6.5 2.7 1.09
CB4.4 - Cove Point 10.2 10.5 10 7.1 3.5 1.6
CB5.1W - Mouth of Patuxent River 9.6 12 12.4 8.6 9.2 7.2
CB5.1 - Cedar Point 10.2 10.4 10.2 7.2 2.3 2.05
CB5.2 - Point No Point 10.3 10.2 10.4 7.5 5.6 2.55
CB5.3 - Smith Point 10.5 10.1 10.7 9.4 6.6 4.3

Bottom Dissolved Oxygen (mg/l)
0.0 - 0.2 (anoxia - kills most life)
0.2 - 2.0 (hypoxia - harms bottom organisms)
2.0 - 3.0 (stresses smaller fish and crabs)
3.0 - 5.0 (stresses larger fish)
5.0 - 10.0 (healthy)
10.0 + (could indicate an algal bloom in summer)
No Data

Dissolved oxygen (DO) in the water sustains life for Bay organisms. Nutrients, such as nitrogen and phosphorus, from agricultural, sewer/septic and urban sources can fuel algal blooms that can starve the water of DO. DO levels above 5 mg/l are normally sufficient to support most life.

More info on: "Our Monitoring Explained"