Salamanca, which is within the Allegany Indian Reservation of the Seneca Nation of New York, is just a short way upriver of the Allegheny reservoir, west of Olean. The downtown district was built along the river and like so many other towns in the Southern Tier, it was severely damaged in 1972. All three bridges that connected different neighborhoods were closed at once due to the flooding, effectively turning the three connected areas of Salamanca into isolated islands.
In the days leading up to the flood, residents had been reassured that their local dikes were tall enough for the flooding river. The local newspaper quoted Salamanca Common Councilors for saying the newly constructed dikes, which were 1380 feet above sea level, would protect the city "from virtually any flood imaginable."
On the night of June 23, Salamanca’s mayor, Kenneth L Reed, imposed a curfew and evacuation order. By 4 a.m. on Friday, June 24, the water poured over the dikes. The river crested at 2 p.m. and held at a level that was over seven feet higher than any previous flood.
Several hundred residents were evacuated to a refuge on the Seneca Reservation.