Here’s a shot of the pole in Ellicott City which shows the heights of flood waters over the last 150 years. What’s almost as shocking as the fact that the water once reached 21+ feet over street level, is the fact that the second highest level was reached in the 70′s, firmly after the Patapsco had been dammed further upstream. A little research has shown me that this flood was the result of Hurricane Agnes. Perhaps when the gates of the dams upsteam were overwhelmed, this is what happened.