They had 'ways'
They are opposites to each other. A drought is no water, but a flood is too much.
The opposite of a flood would be a drought.
a drought
The antonym of drought is abundance or flood.
Drought.
Flood
a flood happens when there is a drought then it rains a lot then it creates a floof that makes a flood
flood
They really did not predict - they just realised that it happened at the same period each year.
A drought is a prolonged period without rain. The opposite would be a deluge, or a flood.
Drought or shortage
because they are IDOIT'S