River Altier
Get-in: The road halfway between Villefort and Pied-de-Borne at an old ruin.
Get-out: Pied-de-Borne where you arrive in the Chassezac.
Pool-drop river, seldom water due to a dam in Villefort, so it needs needs rain. Not too much water either, cause of the pool drop.
A couple of portages, one siphon, one scary fall.