Maryland Annual Tidal Waters Survey Points To Agriculture And Septic Systems As Risk Factors In Calvert County

PRINCE FREDERICK, Md. — The University of Maryland Center for Environmental Science presented its annual report on the health of Calvert County’s tidal waters and creeks at the Aug. 4 Board of County Commissioners (BOCC) meeting, highlighting the ongoing risks of pollution in the Chesapeake.

The Center for Environmental Science has been monitoring the tidal creeks in Calvert County since 1987. The program monitors oxygen, algae and phytoplankton blooms as key metrics of the health of the tidal creeks.

Staff scientist Cynthia Ross said these indicators are signs of the overall health of the Bay and its tidal waters because they occur as a result of excess pollution and poor water quality. In an area like Calvert County, where the Bay’s health is intertwined with the health of the water and the land, these indicators are vital to help with responsible planning in the area.

“If we think of the pollution in the Chesapeake Bay as a disease, these would be the symptoms of that disease,” Ross said.

2025 was an “average” year for all three metrics. Ross noted that because runoff is such a significant factor in water quality, rainy years typically result in worse results.

The biggest challenges facing the county are agricultural runoff and outdated septic systems, which can result in fecal bacteria in the tidal creeks. Agricultural land was a “significant indicator” of poor water quality due to both sediment and phosphorus input. Investing in hydrology, or the way the water flows across the land, could help mitigate pollution from agricultural runoff. The group also recommended prioritizing septic updates in Mill, Plum and Hungerford creeks.

During the presentation, Ross also called out the “generosity and hospitality” of residents and groups in Calvert County as her team worked to complete the study throughout the year.

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