Low tide

at King's Lynn, Norfolk UK. The river flows off to the right to the Wash and North Sea. You can see how little the actual river contributes to the total amount of water here at most times of day, just look at where the high water mark is. The tide dominates and governs the direction of flow.

The skippers judge their sailing and return times to coincide with the ebbing and flow of the tide. As you can see sailing is only possible either side of high tide.

It has been a rather wet day.