Approximate area of Ivan river flooding (i.e., the big Sunday flood, not the Friday small stream flooding) based on comparing water depth with elevations.
This crude elevation data set missed 6th St. (and lots else). The safe height of land in the middle of town is obvious from these maps. See 'Agnes' below, for comparison.
Approximate area of the 1972 'Agnes' flooding. This was the "flood of record" -- biggest ever observed. Agnes was 34' depth, vs 26 for Ivan.
See that this 1967 topographic map still has the buildings where Hufnagle Park is now ... the buildings that were washed out by Agnes.