"Mississippi Heavy Water Blues", by Barbecue Bob, 1927

"Mississippi Low-Levee Blues" also by Barbecue Bob, 1927 (or so)

"Big River" by Zachary Richard (zydeco) (lyrics only, at the link), late 20th century

Eric Bibb, "Flood Water" - I can't find more on this one, also late 20th century.

(thanks for tips from the Wikipedia article on the 1927 flood)