Floodwater can carry various contaminants and parasites. This can pose a risk to your remaining plants and to the soil.  It's best to toss any plants that came into direct contact with the floodwater, including underground plants.  Test your soil next year to make sure it contains no contaminants.  The U of Mn soil test lab - https://soiltest.cfans.umn.edu/ -  can do this for you.  Consider raised beds, moving the garden or digging drainage furrows in the future.  The U of Wisconsin believes that some produce can be salvaged in certain conditions, but keep in mind that your flooding lasted 3 days and contained water that may be polluted.  Here is the U of Wi link - https://ccetompkins.org/resources/safely-using-produce-from-flooded-gardens