Consider the following two images of the Salt River in Phoenix, from the Mill Avenue Bridge.
The former is a flood of the Salt River in 1938.
http://azmemory.azlibrary.gov/cdm/ref/collection/histphotos/id/7227
The latter is a postcard from 1920. http://azmemory.azlibrary.gov/cdm/singleitem/collection/histphotos/id/5354/rec/13
What is the story of the two images?