The Wednesday Wetness

The Baynet, Potomac River Reaches 94 Degrees As Fish Kill Reported In Maryland

Record-breaking water temperatures likely contributed to a fish kill in the Potomac River near Seneca, where Maryland environmental officials recorded an extraordinary 94-degree water temperature following days of extreme heat across the region.

The Maryland Department of the Environment (MDE) confirmed the fish kill in a social media post, saying, “We’re aware of reports of a fish kill in the Potomac River near Seneca. Our biologist recorded water temperatures at a record 94°F. This can trigger a summer turnover event, when layered warm and cold water suddenly mix and oxygen-poor water rises to the surface, stressing fish.”

Although the fish kill occurred in Montgomery County, the Potomac River flows south along the borders of Charles and St. Mary’s counties before emptying into the Chesapeake Bay, making the conditions noteworthy for residents, anglers and boaters throughout Southern Maryland.

The fish kill follows several days of dangerous heat across Maryland and the Mid-Atlantic. Air temperatures climbed into the upper 90s and low 100s across much of the state, with parts of Montgomery County reaching about 100 degrees and nearby Washington, D.C., reaching 102 degrees during the recent heat wave.
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State officials have not announced how many fish were affected or identified the species involved.

If I'm reading the map right, this fish kill occurred up in the riverine Potomac, above Great Falls. I'm not sure I understand their argument about the summer turnover event. However, it was really hot for a few days there.