Here are the estimated water levels (in metres) according to the tidal range at La Rochelle.
Please note : According to weather situation (wind direction, atmosperical pressure…) those can vary+/- 0.30m
| Coefficient | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 110 | 120 |
| Low waters | 3,20 | 2,90 | 2,60 | 2,30 | 2,00 | 1,70 | 1,40 | 1,10 | 0,80 | 0,50 | 0,15 |
| High waters | 4,30 | 4,50 | 4,80 | 5,00 | 5,20 | 5,45 | 5,70 | 5,90 | 6,10 | 6,40 | 6,70 |
| Tidal basins, Vieux Port | Lock opens: | Lock closes: |
| Basin “Des Yachts” | 2h30 before high Tide | 1h00 after high Tide |
| Basin “Des Chalutiers” | 2h00 before high Tide | 1h30 after high Tide |