As we continue the cycle we're in of larger, more frequent and stronger storms, the pressures on these systems are intensifying. The attached article discusses the impacts not only on the Susquehanna, but since it empties into the Chesapeake Bay, the impacts it's having downstream on the Bay's water quality, habitat and fisheries including the all important blue claw crab.
https://earthobservatory.nasa.gov/im...chesapeake-bay
Look at the sediment flowing in from the Susquehanna in the attached aerial image. Reality is all these big systems when we get the kind of rains we've been getting for the past so many years, they all turn the color of coffee and are being filled with urban runoff, increased farmland runoff filled with herbicides, pesticides and urban sediment.
The impacts are changing the ecological factors in the systems and introducing risk factors many of these fisheries never before encountered. As Bob pointed out, the Susquehanna in high weather flows is a turbulent coffee colored river of mud, debris and sediment carrying who knows what toxins into the system. If agriculture, increased urbanization and weather patterns don't change, the challenges facing these great rivers will only intensify and the bodies of water they feed into will face the same challenges.
No different than the Delaware middle to lower sections, Schuylkill, Allegheny etc, any big system surrounded by farming and urban development. Don't know what the answers are but greed, more mouths to feed on this planet and continued destruction of habitat due to urban development are posing serious threats to these great rivers and bodies of water. Combine that with changes in weather patterns most likely driven by climate change and these systems and the species calling them home are being pushed to the brink.