About aruvi āmpal in Patiṟṟuppattu 63, line 19:

aṭaiyaṭuppaṟiyā varuvi yāmpal

āyita vel̥l̥a vūḻi

vāḻiyāta vāḻiya palavē.

O Vāḻiyātaṉ, may you live long, living through the great floods of thousand Kalpas (ūḻi), (floods) which make a loud noise (āmpal) produced by waterfalls ([v]aruvi) and which (the floods, of else the waterfalls, in which case "and" is to be deleted) are unstoppable (aṭai aṭuppa aṟiyā)

One of the meanings of āmpal is the music (noise) produced by blowing through a pipe. It is not exactly the type of noise produced by a waterfall.

I had already removed the mails by Palaniappan and Jean-Luc. Therefore this reaction is not attached to their exchange, which took place under the wrong heading anyhow (The date of ...), a topic, which, as you will know, is otherwise close to my heart.

With kind regards

Herman