Floods in London after 70mm of rain fell in 90 minutes. Yes that is heavy rainfall but should not have led to flood waters a metre high. The reason being that we have paved over vast areas of our cities and towns to create parking spaces. What we really need is to create more sponge type areas. mature trees can absorb 250lts or more per day, with the added benefit of ameliorating temperature extremes, and during hot spells providing welcome shade and habitats for wildlife.