Baïse

The Baïse or Grande Baïse () is a French river that flows through the Hautes-Pyrénées, Gers and Lot-et-Garonne departments, in the Occitanie and Nouvelle-Aquitaine regions.
The river's source is in the Pyrenees and is a left tributary of the Garonne river. In general, it flows from south to north.
Geography.
The Baïse river has a length of and a drainage basin with an area of .
Its average yearly discharge is at Nérac, a small town of the Lot-et-Garonne department that is at about of the confluence with the Garonne river. The largest discharges are during winter and spring, with in February.
Average monthly discharge (m3/s) at Nérac
Course.
The source of the Baïse is on the Plateau de Lannemezan, in the Capvern "commune" (Hautes-Pyrénées), at an altitude of about .
The Baïse flows through 2 regions, 3 departments and 52 "communes". Some of the "communes" are:
Finally, it flows into the Garonne river at Saint-Léger (Lot-et-Garonne), at of altitude.