In the 20 years I've been with Arup, I've worked...
Rivers are phenomenal assets, but they can also be a hazard. Around the world, flooding from rivers threatens communities and holds back regeneration. If we show the necessary wisdom in managing this threat, it should be possible to ensure that rivers achieve their full potential as hugely valuable assets for communities and society.
Rivers variously act as sources of water and food, navigation routes, power generators, drainage conduits and receptors for treated sewage effluent. They are also outdoor swimming and boating venues, catalysts for spiritual renewal, muses for poets, writers and artists, and homes for a startlingly diverse range of plants and animals.
No wonder research has demonstrated that proximity to rivers has a greater positive impact on house prices than any other natural amenity. Healthy rivers regenerate communities. The restoration of Cheonggyecheon Stream in Seoul, for example, has served as a catalyst for an estimated $1.98 billion USD worth of capital investment in the Cheonggyecheon-area – redevelopment that would not have otherwise been invested.
However, the nearer you live to a river the more likely you are to be at risk of flooding. Only those who have experienced flooding know the true extent of the devastation it causes to the buildings, possessions and health of those affected. Ironically, given the link between rivers and high property values, there is also an established link between social deprivation and flood risk. In the UK for example, the most deprived proportions of the population are 62% more likely to be living in areas at high risk of flooding.
So why is it that, while the presence of a river can markedly increase property values, social deprivation is also more prevalent in areas of heightened flood risk?
I think the answer is quite simple.
Success occurs where human development is wise to the hazard rivers pose, leaves space for floodwaters and retains the essential natural characteristics of river functioning that make living by a river so attractive. This truth is now widely appreciated by communities such as Cedar Rapids in the US, where the city authorities have developed a compelling vision of a brighter future following a devastating flood in 2008.
There are many reasons why such success has not always occurred - and these are all related to floodplain occupancy of one kind or another. The history of urban and industrial settlement saw a ruthless and unsustainable exploitation of rivers - primarily for navigation, power generation and waste disposal. This often left them in such a degraded state that they ended up as little more than open sewers.
We turned our backs on our rivers. Many were even piped below ground. And so the close connection of respect and understanding that once existed between man and the vagaries of natural rivers was severed. Cities such as Sheffield, Manchester and London in the UK are teaming with ‘lost’ rivers and streams, many of which have been incorporated into the wider sewerage network. Deterioration of these historic sewers and culverts, coupled with an increased frequency of intense storm rainfall due to climate change, now presents civic authorities with some major challenges.
So now more than ever it is time to redress the balance, to restore our rivers and celebrate the ecosystem services they provide. In particular, we should optimise the positive impacts that rivers have on human health and wellbeing, but also recognise the powerful role they can play as catalysts for economic regeneration.
To achieve this we will need to ensure that where we do occupy floodplains we do so wisely, respectfully and with the precaution required to ensure the long-term resilience of our assets and communities.
We can – and should – live alongside rivers. We just need to manage the risks intelligently.