I have taken so many pictures of the river, or looking out to sea, and have posted a number of them here, so I thought I would have trouble picking out one more for this prompt. But in fact, I took this picture this week and when I downloaded it from my camera it seemed to choose itself.
The mouth of the river, early on a summer's morning.
It is half tide and that island is the highest point of a bank called The Black Middens. It is covered at full tide and in the days before ships had engines was the cause of a number of wrecks.