| name | image | Average flow (m³/s) | basin (m²) | Height (m) | origin location | mouth location | Length (m) | latitude (°) | longitude (°) | canyon | Map |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Bevera (affluente dell27Olona) | 435 | Olona | 81,000 | 45.8078326000 | 8.8669418000 | Map | |||||
| Bozzente | 1 | 150,000,000 | Olona | 37,000 | 45.7830555556 | 8.9589916667 | Map | ||||
| Fredda | Olona | 4,000 | |||||||||
| Gaggiolo |  | 0 | 94,000,000 | Olona | 22,000 | 45.8004166700 | 8.8723611100 | Map | |||
| Merlata | 1 | Olona | 4,000 | 45.5247805556 | 9.1096555556 | Map |