This place often floods - it's designed to, that's why it's called the Washes. Allowing this area to flood quite deeply, between high embankments, protects huge areas of farmland in the Fens from getting flooded.
The railway crosses the washes on a high enough embankment to remain open, but the road has to be closed. On the print, you can see the depth gauges each side of the road: it was about 4'4" deep when I took the picture.
It's quite a long detour when the road's closed.
It's a great place for water birds when it's flooded.
A lovely photo; I like the play of light over the water, and the calm atmosphere, (which may be because I can't hear all the grumpy drivers muttering about having to take the detour!)
The grumpy drivers would be a couple of miles back, where the "road closed" signs were - unless any of them thought they might be able to get through, and only realized they couldn't when they saw it was over four feet deep!