Last week I introduced you to the lovely River Camel in Cornwall.
It’s a small river, with a massive estuary, as the sea has flooded the lower river valley forming a ria.
At low tide there are sandy / muddy deposits everywhere and look how quickly tributary streams form mini river features, as they meander to the main channel, before the tide comes in again.
Where has all this stuff come from? You might think that with a river flowing through, everything would be washed out to sea. That works well enough when the tide is going out but half the time the tide is coming in. The river flowing out then meets the sea coming in and the speed of both of them is checked.
As soon as speed slows down, ability to carry stuff is reduced and both the sea and the river dump material in the estuary, creating the sand banks and mud flats.
It’s all soft and loose so as the tide goes out the river carves a path through, but if you want to bring a boat in it is best to come in with the tide, so that if you run aground the tide can lift the boat free.