Record Amounts of Rainwater Flow off the Land into Chesapeake Bay

Science Center Objects

As the Mid-Atlantic states' super-soaker summer draws to a close, record amounts of rainwater have flowed off the land and into Chesapeake Bay, with potential consequences for the nation's largest estuary. USGS measurements show freshwater flows into the bay in August 2018 were the highest ever recorded for that month by a wide margin. River flows into the bay have been unusually high since May.

Summer months usually carry the smallest river flows to Chesapeake Bay. But since June 1, more than twice the normal amount of rainfall has fallen over a broad swath from Washington, DC through central Pennsylvania, according to the National Atmospheric and Oceanic Administration (https://www.climate.gov/news-features/event-tracker/soggy-summer-mid-atlantic-2018), which points to a long-lasting low pressure system over the eastern U.S.

High river flows usually carry more pollutants into the bay and affect salinity levels, which in turn can affect oysters and fish, underwater grasses and other facets of the bay ecosystem. USGS scientists and other partners are collecting information to assess the impacts of the high flows on water quality and fisheries. For more information on flows to the bay see the web page, Chesapeake Bay Estimated Streamflow.

 

The five highest freshwater flows into Chesapeake Bay ever recorded in the month of August.

The five highest freshwater flows into Chesapeake Bay ever recorded in the month of August. Credit: Wendy McPherson, USGS
(Public domain.)

Susquehanna River water flowing into the Chesapeake Bay in August 2018.

Susquehanna River water flowing into the Chesapeake Bay in August 2018.
(Credit: Joel Blomquist, USGS. Public domain.)

 

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