Question

Floodplains are most often found for rivers that exist on

Answer 1

Answer:

areas that get high rainfall... im pretty sure

Explanation:

Answer 2

I am pretty sure that floodplains are most often found for rivers that exist on 
hilly areas at the base of mountains. In order to give yoy ans example which will make sure that this answer is quite a suitable one, nice example of floodplains
is The Virgin River at the upper end of Zion Canyon. It will definitely help you! Regards.