Bay’s Dead Zone Smallest since 1985

Data released by the Chesapeake Bay Program’s monitoring partners: the Maryland Department of Natural Resources, Old Dominion University and Virginia Institute of Marine Science show that this summer’s Chesapeake Bay “dead zone” was the smallest it’s been since monitoring began in 1985.

The new measurements confirm the June 2023 Chesapeake Bay forecast, which predicted the smallest dead zone on record. The model used to make the annual forecasts was developed at the University of Michigan.

Based on water quality data provided by the Maryland Department of Natural Resources, the Virginia Department of Environmental Quality and Old Dominion University, the Maryland Department of Natural Resources and the Virginia Institute of Marine Science independently estimated the size of the dead zone from May to October 2023 using separate methods.

They then calculated hypoxic volume within the bay’s main stem from that time period. The Maryland Department of Natural Resources found that hypoxic water volume averaged 0.52 cubic miles, while the Virginia Institute of Marine Science reported a similarly low estimate of 0.58 cubic miles.

Both estimates are the lowest on record and much lower than the historical average of 0.97 cubic miles taken from 1985-2022.

Two reports are available based on this data: the Virginia Institute of Marine Science in their 2023 Chesapeake Bay Dead Zone Report Card, and the Maryland Department of Natural Resources in their 2023 Final Hypoxia Report.