Researchers: Calvert County’s 2024 water‑quality monitoring shows generally improved oxygen but flags Parker’s Creek algae uptick

Researchers from the University of Maryland Center for Environmental Science’s Chesapeake Biological Laboratory and Calvert County planning staff presented the 2024 Bridal Creeks water‑quality monitoring results on June 3, summarizing long‑term trends across Solomons Harbor and 11 tidal tributaries.

Jeremy Testa (Chesapeake Biological Laboratory) told the board that 2024 ranked among the better years on record for bottom‑water dissolved oxygen — “it was the 4th best year on record” — and that algae/bloom metrics were near the long‑term average. Testa emphasized that weather drives much year‑to‑year variability: wet years can bring higher nutrient loads and reduce oxygen, while dry years can show better conditions.

Across most monitored creeks, bottom‑water oxygen concentrations improved or were above recent averages in 2024. However, the presenters called attention to Parkers Creek, where statistical trend tests showed an uptick in chlorophyll a driven in part by a high value in the most recent summer. Testa and colleagues cautioned that a single high year can drive a statistical signal and recommended continued monitoring to confirm whether this represents a sustained trend.

The team also summarized microbiological findings: average coliform measures at four Mill Creek stations were below thresholds used for shellfish or swimming closures, and there were zero reported non‑cholera Vibrio cases in Calvert County in 2024 (state totals were preliminary).

Planning staff noted a fiscal 2024 contracted services expenditure of $17,659.50 under contract number 22020O93 for the monitoring program. Testa outlined recommendations: continue partnerships with volunteer groups and state programs, target local nutrient‑source interventions (including septic upgrades and selective sewering where feasible), support education, and pursue integrated mitigation that also addresses flooding. He described ongoing work to develop a higher‑resolution Patuxent estuary model and a Maryland Sea Grant‑funded analysis to prioritize watershed interventions.

Commissioners and staff discussed tradeoffs between centralized sewer systems and BAT (best available technology) septic systems, potential pump‑out programs, homeowner costs, and the need for engineering and cost studies before large‑scale infrastructure changes. County volunteer monitoring groups were encouraged to share their datasets for integration and technical assistance.

Presenters said the long time series of monitoring shows the systems are responsive and that targeted restoration and careful planning could yield measurable improvements over time. The board thanked the presenters and noted the county will continue to partner with CBL and local volunteer groups on monitoring and targeted restoration planning.