Flooding.

On my way to work yesterday (Friday) morning my way was blocked by a flooded underpass on Hitchin Road. Although it was still dark, it was obvious that this route was completely impassable.
After work I returned that way to have a better look.It had been raining fairly persistently through Thursday night, but I was amazed at the volume of water; where had it all come from? I have never seen this underpass flooded before.
This is what it looked like:

Looking south from the shared footpath/cycleway (NCR12). The route follows the right hand side of the fence, straight into the water.

Looking north. The two black dots in the water just left of the lamp standard are the tips of wooden posts placed to keep users of motor vehicles from using this route.

Looking out across the flooded field.

The water in the underpass must be 2m deep.I assumed at the time that this enormous volume of water had something to do with the pumping station just out of shot - perhaps using the field as an emergency storage reservoir. However, once I reached home I saw lots of pictures on the internet of localised flooding in the Hitchin, Stevenage, Hertford area. I can only conclude that the land is now so saturated that all of Thursday night's rainfall remained above ground and just ran downhill until it could go no further.

Obviously I appreciate that these floods are insignificant compared to others around the country, but they are novel to me, living as I do in such a dry, well drained region.