This week David takes a look at what can be done in urban areas to prevent the causes of flooding:
‘In the six hundredth year of Noah’s life . . . were all the fountains of the great deep broken up, and the windows of the heaven were opened. And the rain was upon the earth forty days and forty nights.’
We all know the story of Noah and the ark in which he and his family floated while God cleansed the earth of wickedness. You may not know, however, that the story of Noah is just one of hundreds of ancient stories in which vengeful or sorrowful gods felt that the only way to re-establish the human race on a better plan was to drown virtually all of them.
Do you know of the myth of Deucalion, the Greek and Roman equivalent of Noah? Or of Gilgamesh of Sumeria? Perhaps – they are among the better known of the ancient Noah equivalents. But what about the Finnish flood myths, where the blood of the wounded hero Väinämöinen floods the world? Or of Tamanduare, from Brazil, who with his wife alone escaped the flood sent by the god Tupi? Or Djunban of Australia, whose rain-dance was too successful, or Pawpaw Nan-chaung in Burma, who escaped the flood, Noah-like, in a boat or of the Inuit man Kunyan who floated to safety on a raft?
Floods are part of our common history as well as of our experience today. In all the ancient tales, floods are seen in two ways – as horrifyingly destructive and as a way of purging evil. There was an acceptance that floods were hardly to be tamed but had to be either endured or, if possible, circumvented and made use of. Many ancient civilisations relied on the floods – from the origins of civilised humanity in Mesopotamia, where the Tigris and Euphrates regularly flooded, to Egypt, where the Nile was the great giver that irrigated and fertilised the land.
So how do we view flooding today? The question is pertinent, as last Friday saw the official opening of the Ripon flood alleviation scheme, when the Environment Agency presented the Mayor of Ripon with a plaque marking the work. The previous week, Ripon Civic Society gave the scheme one of its environmental awards.
Note the name of the project – flood alleviation. It is not flood defence. As the ancient peoples knew, if the gods are angry and send the floods, there can be no secure protection. What the scheme does is to lessen the impact of floods, and reduce the number of properties inundated during a severe flood. The Ripon scheme incorporates a flood storage reservoir upstream on the River Laver, new measures at Borrage Lane, new embankments at North Bridge and by Fisher Green, and the new weir at the Alma Bridge. According to the Environment Agency, this will reduce the chance of Ripon homes flooding from as high as 10 per cent in a year to one per cent.
There is no claim – nor can there be – that flooding risk is eliminated. And floods would seem to be getting more frequent; the Ripon scheme has been severely tested three times since its recent completion, most recently by some of the most severe flooding since 2000.
Why are we getting more floods? Obviously, because there is more rain. Many today would attribute that to the warming of the climate. The arguments sway to and fro (like floodwater), but the scientific consensus is that through the actions of mankind the climate is altering, allowing more severe extremes of weather all around the world.
If we accept that there is more rain – whatever the cause – is that it? Are we getting greater problems with floods merely from the sheer volume of water? Obviously not. Our activities are also making flooding worse. Changes in agricultural methods, the removal of trees and the draining of land into watercourses have all had the effect of reducing the amount of water that can be absorbed by the land and increasing the flow of water down our streams and rivers. Inevitably, the effects are felt downstream – and is cumulative. York gets worse flooding than Ripon, because Ripon’s three rivers feed eventually into the Ouse – and so do many other Yorkshire rivers. Downstream from York – at Cawood and Selby, for example – the effect is even greater.
But it’s not just in the countryside that problems are being built up – and built up is the phrase. Every time that a new development is created we also create more problems in the disposal of water. It’s not just the water we use in our buildings, but the water that falls on their roofs and on the impervious pavements and roads that surround them that is the problem. If the water cannot penetrate the surface of the ground, it must find other channels – and in heavy rain our drains cannot cope. That’s why we have urban flooding.
So what can we do? We need to deal with the cause, not just the symptoms. The flood alleviation schemes deal with the problems created, but are not a solution. Our ancestors knew that when rivers flood they create flood plains; they recognised the fertility of them and used them for grazing and cropping, but not for building on. We, though, have built on flood plains, so we should not be surprised if the properties flood. We are, perhaps, at last waking up to this fact.
But there is still far too much covering the land with hard surfaces. We need to insist on surfaces – especially for places like car parks and drives – that are tough yet let the water through. There are plenty on the market – we need the political will to insist on them. And we need to encourage the use of rainwater for domestic purposes, to make it work harder, not just for watering the garden but for many other uses in the house. Simple measures can have a great effect.
So, although we cannot prevent floods, we can mitigate the problems. This should be a priority for us all – otherwise, we should be ordering our arks.