Current Conditions Yearly Table View

The table below shows the most recently collected long term fixed station data, as well as comparisons of current conditions with historical averages.

Notice: The data provided in the table below is also available in a text-based accessible data table.
Select a Year, Sampling Location, and Parameter:

2026 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 (Conowingo) 13.5
CB1.1 - Mouth of Susquehanna River 13.9
CB2.1 - Turkey Point 13.4
CB2.2 - Still Pond 12.3
CB3.1 - Gunpowder Neck 10.3
CB3.2 - Swan Point 9.1
CB3.3W - Bay Bridge (NW)
CB3.3E - Bay Bridge (NE)
CB3.3C - Bay Bridge (N) 9
CB4.1C - Kent Point (SW) 9.2
CB4.1E - Kent Point (S)
CB4.1W - Horseshoe Point
CB4.2E - Tilghman Island
CB4.2C - MD Mid Bay 9.2
CB4.2W - Plum Point
CB4.3W - Dares Beach
CB4.3E - Mouth of Choptank River
CB4.3C - Dares Beach 9.4
CB4.4 - Cove Point 9.5
CB5.1W - Mouth of Patuxent River 11.6
CB5.1 - Cedar Point 9.9
CB5.2 - Point No Point 10.3
CB5.3 - Smith Point 10.3

Bottom Dissolved Oxygen (mg/l)
  • Purple 0.0 - 0.2 (anoxia - kills most life)
  • Red 0.2 - 2.0 (hypoxia - harms bottom organisms)
  • Orange 2.0 - 3.0 (stresses smaller fish and crabs)
  • Yellow 3.0 - 5.0 (stresses larger fish)
  • Green 5.0 - 10.0 (healthy)
  • Blue 10.0 + (could indicate an algal bloom in summer)
  • Gray 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" (opens in a new tab)