River Flow to Chesapeake Bay Near Record Levels in July 2018

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The Total River Flow into Chesapeake Bay in July 2018 was the Second Highest on Record

The U.S. Geological Survey estimated monthly mean streamflow entering Chesapeake Bay for July 2018 was 100,000 cubic feet per second (cfs). This was the second highest value for the month of July, only behind July 1972, when the Chesapeake was still experiencing the effects from Tropical Storm Agnes.

Susquehanna River July flows to the Bay sets a record

The Susquehanna River had the highest flows for a July since estimates began in 1937. The July river flows were an unusual summer storm, in that they were not associated with a hurricane or tropical depression. The National Weather Service reported widespread heavy precipitation throughout the Susquehanna watershed, with particularly heavy amounts in the South-Central Pennsylvania.

The flows on the Susquehanna River at Conowingo, Maryland, peaked at 375,000 cubic feet per second on July 26 2018 (see graph). Flows of this magnitude can be expected to occur about once every 4 to 5 years, however this was the highest flow since Tropical Storm Lee in 2011. The long-term average flow for the Susquehanna River at Conowingo, Maryland, is 40,700 cubic feet per second.

Graph showing Susquehanna River at Conowingo 2018

Additional information
More information on the July and other river flows to Chesapeake Bay can be found at Estimated Streamflow Entering Chesapeake Bay.


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