Firstly, we have a picture near to Bait's Bite Lock. In the immediate foreground is the brick edge of the bridge the carries the Cam towpath over the Award (I believe) drain. The far bank of the Cam can be made out.
Then we have the A1101 at Welney from the Delph Bridge. Note that the road bed varies in height. By the speed limit sign on the left, the water is about 3 feet deep on the road. By the one on the right it is another foot or so. In the distance you can just make out the chevrons for the right turn. Estimates from locals put the depth two bends further on at about 5 feet. Later that day, the Environment Agency built a large barricade from sand and plastic on the bridge about 6 feet higher so obviously expecting the worst. Such a barrier has not been built in living memory, although a less substantial one was put in last Easter.
Here is a picture from the A1101 verge across the Washes. I estimate about 70,000,000,000 gallons of water were lying between the banks.
Finally this is
a shot of the high bank. On the left is the Delph River and the Washes.
On the right is the Old Bedford River. It is hard to tell from the
photograph but you should be able to work out the relative heights of the
rivers and also the land to the right. Note that this land is not
below sea level.