I have seen the Monocacy river in Maryland basically die below the City of Frederick over the last 35 years due to farming practices, feed lots, high density housing developments, and the amount of water the City of Frederick takes from the river every year. It was once a unbelievably vibrant fishery. Now it is like a dead river until the Double Pipe feeds in and the Double Pipe is in bad shape. While Global warming has not been a factor since 1998 new housing developments and intensive farming practices have all taken their toll. Green house operations, some farms, and feed lots a long with the City of Frederick take huge amounts of water out of the river during the summer months when the flows tend to be low anyway and this has turned many of the river's beautiful boulder holes into dead pools that can barely support carp. The water they return to the river is so putrid that you would not want to be anywhere near it. I have seen huge die offs of largemouth, smallmouth, fresh water mussels, and even crayfish during the Spring and Summer months. I can't help, but wonder if the Susquehana river is just a larger example of this same sad situation.