| name | image | Average flow (m³/s) | basin (m²) | Height (m) | origin location | mouth location | Length (m) | latitude (°) | longitude (°) | canyon | Map |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Arçon |  | 280 | Gers | 18,100 | |||||||
| Auchie | Gers | 14,000 | 43.9983333333 | 0.5833333333 | Map | ||||||
| Aulouste | 70,000,000 | Montaut-les-Créneaux | Gers | 20,600 | 43.6767000000 | 0.6855000000 | Map | ||||
| Cédon | 335,000,000 | Gers | 18,600 | 43.6074700000 | 0.5965000000 | Map | |||||
| Cier | 84,000,000 | Gers | 13,600 |