We were up in the north of Scotland and went to see the dolphins at Chanonry Point on the Moray Firth. It is a narrow spit over a mile long that sticks out into the estuary. There's a road down it and a golf course, but it narrows to a shingle spit shown below.
On the rising tide, there is water coming in from the sea on your left. Meanwhile, river water is going out to sea from the right. The result is a stationary wave. It can't quite be the classic case that I teach about when the two waves are in opposite directions with same speed, frequency and amplitude, but you do get a wave feature that stays fixed in the same place on the sea. The waves go up and down but don't go left or right. You can see it as white water above the crowd in the picture above. It is clear on the water in the picture below.
The current carves a deep channel just off the end of the spit and the resident population of bottle-nosed dolphins gather to feed on salmon on the rising tide. Huge crowds gather to watch the spectacle. We saw at least a dozen dolphins, some of which are shown below. They performed as well, jumping clean out of the water. It is said to be the best place in Europe to see dolphins from the land. They can be as close as a few metres. You ought to go. If you don't like dolphins, go for the waves.
