Question

why piedmont alluvial plains are found along the foothills of mountains​

Answer 1

Here is your answer,

                   

Along the foothills of mountains there exists a humid climate and Piedmont, in geology, landform created at the foot of a mountain.

This is the reason why piedmont alluvial plains are found along the foothills of mountains​ well because of the capability of suitableness and These alluvial fans typically form in elevated or even mountainous regions.

                       

Hope it helps...............................

Answer 2

Explanation:

as the river leaves mountains and enters the Plain region the slope of the land changes from steep to gentle so it is difficult for the river to carry its eroded material that is pebbles, boulders etc.with it .The river starts depositing its load at the foot hill area of the mountain and form piedmont alluvial plains. This is also called BHABAR in India.