How high? Fifty seven feet. That’s where the Ohio River crowned after flooding its banks in Louisville. Markers around town, in such locations as The Highlands, Portland and Crestwood, give a visual sense of just how high it was. Those markers, and the exhibition “How High the Water Was: The Flood of ’37,” remind us how dangerous it was here 80 years ago. Historian Tom Owen is giving a talk, “Observations on the Flood of 1937,” on Sunday, Feb. 19 at 3 p.m. in the Ekstrom Library’s Chao Auditorium. The exhibition is from 2-5 p.m., the only weekend hours scheduled during the show’s run.