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Current Conditions Yearly Table View

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2020 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 13 12.6 13.5 8.1 7.7 7.3 7.5
CB1.1 - Susquehanna River 12.6 12.7 8.8 7.2 5.95 7.05 8.2
CB2.1 - Turkey Point 12.4 12.4 8.3 7.8 6.2 7.35 7.7
CB2.2 - Still Pond 10.6 11.9 7.1 7.6 5.75 6.1 7.1
CB3.1 - Gunpowder Neck 9.3 10.1 4.5 - 3.3 3.85 5.3
CB3.2 - Swan Point 8.4 9.6 2.4 - 1.59 1.56 4.4
CB3.3W - Bay Bridge (NW) 2.3 2.7 4.9 3.85 3.7
CB3.3E - Bay Bridge (NE) 4.9 3.4 4.3 5.95 5.3
CB3.3C - Bay Bridge 6.7 8.4 2.6 0.64 0.48 0.48 2
CB4.1C - Kent Point (SW) 5.8 8 1.1 0.53 0.64 0.44 2.4
CB4.1E - Kent Point (S) 3 0.61 0.5 0.64 3.4
CB4.1W - Horseshoe Point 3.8 3.4 3 1.75 6.6
CB4.2E - Tilghman Island 6.9 6.2 3.65 6.8 5.5
CB4.2C - MD Mid Bay 6.2 8.3 3 0.92 0.74 0.46 3.4
CB4.2W - Plum Point 4 4.3 1.46 2.2 7.3
CB4.3W - Dares Beach 3 4.4 1.81 2.45 7.2
CB4.3E - Mouth of Choptank River 3.7 1.1 0.8 0.63 3.6
CB4.3C - Dares Beach 6.7 8.3 4 0.7 0.7 0.63 3.3
CB4.4 - Cove Point 6.5 8.9 3.8 1.04 1.06 3.7
CB5.1W - Mouth of Patuxent River 8.1 8.9 6.9 0 5.6 -
CB5.1 - Cedar Point 6.8 8.9 3.9 1.03 1.22 3.8
CB5.2 - Point No Point 6.8 9.1 4.3 1.09 1.18 5.6
CB5.3 - Smith Point 7.7 9.4 4.8 1.47 2.6 6.4

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"