1) Since "flood" is uncountable, replace are with is.
2) Replace "belong" with "belonged," as it's the passive voice. If it implies the present continuous tense, use "belonging," but the first option is preferable.
Please don't think I'm nitpicking; such a large and red phrase should be correct, right?
P.S. If anything, I studied in a linguistics class for 10 years. :o
Bow down and hear our cry,
Our earthly rulers falter,
Our people drift and die,
The walls of gold entomb us,
The swords of scorn divide,
Take not thy thunder from us,
Take away our pride.
G.K. Chesterton: English Hymnal