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Fixed Station Monthly Monitoring

Fixed station monthly monitoring The fixed station monthly monitoring program consists of sites that have been sampled monthly or twice monthly since 1985. Sites are visited by our Research Vessel Kerhin and smaller boats, or accessed via road/ferry crossings. Water quality profiles are taken, as well as nutrient, sediment and chlorophyll samples. Virginia follows identical sampling protocols and full data results are available via the EPA Chesapeake Bay Program Data Hub.

These data are the backbone of the Chesapeake and Coastal Bays management and restoration efforts. They are instrumental in determining the long-term trends and current status of water quality in the region. The data underlie products such as water quality report cards and barometers, as well as models that help to refine watershed management efforts.

Fixed station, monthly monitoring data is currently available for 101 stations. Charts for water temperature, salinity, pH, secchi depth (water clarity), and bottom dissolved oxygen depict the long-term monthly minimum, maximum and average results versus current monthly conditions.

Click here to view a downloadable table of Long Term Fixed Stations, with site coordinates.

Query for charts and a summary table of data below:

1. Choose a station:

2. Choose a parameter:

Bottom dissolved oxygen (mg/L)
Water temperature (°F)
Secchi depth (m)
Salinity (ppt)


Location: Potomac River Between Possum Point and Moss Point
>> Click here to view a station map <<
Coordinates (NAD83):
Latitude: 38.5298°, Longitude: - 77.2653°
View/download table of Fixed Station Information
Description: This station is a tidally influenced fresh water site in the mid-channel of the Potomac River.

2024 Bottom Water Dissolved Oxygen

Bottom Water Dissolved Oxygen (mg/l)

Bottom Water Dissolved Oxygen (mg/l)
Lower Potomac River / Quantico (TF2.4)
Month Minimum Mean Maximum 2023 2024
January 10.60 12.53 14.10 12.70 10.70
February 10.20 12.65 13.90 12.60 11.30
March 10.35 11.82 14.00 11.00 10.50
April 7.85 9.77 12.10 9.60 10.60
May 6.75 8.33 10.20 8.50 8.60
June 5.40 7.04 9.20 7.70 7.00
July 5.00 6.50 8.30 6.00 Not Sampled
August 4.80 6.22 8.20 6.20 Not Sampled
September 4.70 6.26 7.50 5.90 Not Sampled
October 6.06 7.48 8.85 7.50 Not Sampled
November 7.90 9.49 11.00 8.50 Not Sampled
December 8.40 10.98 13.20 10.10 Not Sampled

NOTE: 'Not Sampled' can mean either the station was logistically unable to be sampled, or the data are still in the collection and processing phase. Results displayed are provisional and have not undergone full Quality Assurance procedures, and as such we cannot guarantee their accuracy at this time.