A while ago I wrote a blog post on how the sand banks in this little creek form. Below you see the picture I showed then:
Then, about two weeks ago, I passed that spot again when it was raining, and this is what it looked like:
Now we can actually see the flow field, and we can see that the sand bank in the far back has moved quite a bit. We also see that during the night it must have rained more at some point, since the leaves on the sandbank on the left that got stranded there, must have been carried there by a higher water level.
I went back later that day when it had stopped raining, and then it looked like this:
Now that the water level has sunk again, you can clearly see that the sand banks have shifted compared to where they were in the first picture a couple of weeks ago.
Funny how much you can discover if you actually look at the world around you :-)