[spadlet]

I heard that the floods in Sheffield (flash floods due to a month's rain falling in 24hrs) were affected by the following factors:

The flood in the city centre occured due to a river busting it's banks. This river had at least 4 other rivers feeding into it before the point where it burst it's banks. The some of the flooded areas alongside the river used to be wasteland but have been built upon in the last 5 or so years. This does raise the possibility that they built on a flood plane, which in times of unusually high rainfall would be expected to flood, reducing problems downstream.

The reservoir where the water had to be allowed to flow along the overspill, flooding alot of homes, messing up their insurance and ruining the house proces, has been (I think 6 inches) over capacity before it began raining. Thus the Environment Agency didn't have any leeway when all of that water turned up.

I agree with delboy. I think one of the most sensible things would be to accept that some areas flood, or may be needed to absorb excess water and stop building on them. All along the valley that the train goes through between Manchester Victoria and Leeds there are playing fields etc next to the canal and river, so that flooding is not a major problem in the villiages.

Paving gardens and drives with paving tha allows water to drain into the soil beneath, rather than tarmac, would also help. This is because it reduces the water that gets diverted into the streets, to flow down the hills and collect at the bottom.