As I write this York has just flooded and might flood again tonight. One big cause was some pumps failed, same as Hull and Pateley Bridge. The underlying cause maybe is that the river is not as wide as the old bridges - half width by the sewage works - and the water is backing up. The further downstream the worse it gets until in Selby, after the Wharfe has joined, it is 1/3 of the combined York and Tadcaster bridges.
It does seem a long way downstream but the land is very flat and if the flood water cannot get away it must continually back up.
In York itself the council has built a car park below Skeldergate Bridge taking 1/3 of the river and everybody has leveled and built up the banks. Downstream there are miles of flood banks built too close to the river. This is all right when the river bed is low enough but over the years this fills up with silt, sand, gravel, etc but as the river is restricted it cannot meander and it must overflow. Also the river narrows and gets shallower as it floods between the flood banks leaving sediment - vegetation consolidates and wildlife protects.
This is not rocket science and presumably academia know this but no one is allowed to work in rivers - see " Why Britain floods " on home page.
I have copied the outline of the Ouse bridge, the oldest in York, at 70m wide throughout the site. The blue lines may show where the river banks were when the bridge was built and where they need to be now with global warming. All the car parks, flood banks, etc have been built since. How the authorities are going to clear the river is a problem, even if they can get permission, but if the landowners and farmers were asked and paid they would soon sort it, perhaps for less money.
To make up for the reduced width of the river the depth will have to increase but with the amount of sediment coming downstream, especially after a flood, this is unlikely if not dredged.
The bridge at Tadcaster has just collapsed! No wonder as of the seven arches, two are completely blocked, two are half blocked and three are open but have probably got gravel, etc in the bed. Please will someone clear the rivers.
This town shows how much silt can accumulate if not regularly cleared.