France. The river Landistou [fr], a 12.5 km long tributary of the Béez, passes through the village Lys. Several tributaries of the Landistou (Betbeder, Bonnasserre...

the Escourreix (R) the Soulens, from the Sarramayou (491 m). (L) the Landistou, from Sainte-Colome, Lys and Bruges. also known as Béès or Bez Sandre...

Arthez-d'Asson. The Béez is joined in the commune by the Ruisseaux of Landistou, Trubés (itself fed by the Ruisseau de Marlies), Toupiette, Arrouy, Mourté...