In the 10 years since Katrina, even a less-than-observant eye can see a drastic shift in the French Quarter in terms of musicians who work on our streets. Post-storm, the bulk of buskers has moved from native sons with horns, rhythm and bottle-cap boogie shoes to transplants with fiddles and melancholy melodies.

Among Katrina’s countless consequences, the floodwaters’ damage has seemingly cut into the city’s musical heritage—in one word: ...