Tuesday, 12 January 2016

Flooding - the inconvenient truth

“Flooding equals lack of river dredging” is the simplistic message often promoted by the media, sometimes with bizarre claims that rivers were left un-dredged just to protect wildlife.  Some pundits even go so far as blaming “eco-zealots” for the floods, with accusations that environmentalists are more concerned about bugs and beetles than they are about people!  It’s all so simple in some minds.

To all complex problems there is a solution that is simple, clear, obvious – and wrong!  And this is where we are with some responses to flooding.  The simple solution is the wrong one – the one that makes the effects of flooding far worse.

The practice is that flood risk can be reduced (not eliminated) with careful and sophisticated approaches that actually deliver results, rather than political knee-jerk reactions.  And the practice is that careful management of river catchments to reduce flood risk downstream, also supports a rich and varied wildlife.  Rich wetland wildlife is a sign that we are getting flood management right.

This has been shown time and again. In academic studies, government reports, careful case studies and direct on-the-ground experience.  The problem for the media is that showing an area that didn’t flood because of some careful work done upstream does not make a good story.  “Here’s a place where nothing happened” is not very riveting - far better to show misery and then blame someone.

Clear examples of where a proper approach has worked are places like Pont Bren, the Exmore mires and Pickering where Natural Flood Management has been successfully employed alongside more traditional flood engineering.  Not heard of them?  Of course not – nothing dramatic happened there.  Other examples in the past include management by Yorkshire Wildlife Trust of their Potteric Carr preventing Doncaster from flooding and Hampshire Wildlife Trust managing of their reserve probably preventing flooding in Winchester

Rivers flood for three reasons. 

First of all, lots of rain!  When huge amounts of water fall out of the sky it has to go somewhere.  The maths is actually quite simple, eloquently articulated in a recent farming conference.  The catchment area that picks up the rain is likely to be well over 1000 times larger than the area of the river it eventually goes into.  So 1 inch of rain in the catchment, if delivered to the river all at once, becomes 1000 inches in the river.  No amount of concrete pouring, dredging or defence building will cope with that. If we defend one area then water will go somewhere else.  If we prevent flood plains from flooding (there’s a clue in the name!) then water will move to the next weak point, often an urban area.

Second, what causes increased storminess and more intense rain?  Climate change.  There is little scientific doubt that climate change increases the energy in the system and this increases the incidences and severity of heavy rain storms.  This is no surprise.  Climate scientists have been saying this for 20 years.  Governments have preferred not to hear this and hope it might all just somehow go away.  Storm damage and flooding is therefore another hidden cost of climate change, essentially a cost of burning fossil fuels (coal, oil and gas).  Hidden costs have a habit of not staying hidden for long.  The billions of £ of flood damage and lost productivity to the country is largely an unpaid bill for the fossil fuel industry (paid instead, by us, through the tax system).  If the true cost of fossil fuels was reflected in the price we paid then it would be clear that green energy is a great deal cheaper.

The third reason is catchment management.  How we manage river valleys can increase, or reduce, the flood risk to people downstream.  Building hard flood defences, concreting over land with new development, woodland removal and river dredging upstream forces water ever quicker down the river and just increases flood risk to people downstream.

Building houses in floodplains is nonsensical, and yet it is still allowed.  Even if we protect them with engineering from small floods, we can never stop the big floods.  Furthermore, by preventing flooding in one area, we simply create it in another – maybe this is why areas that have not flooded in the past are now starting to get flooded.

The key is to allow areas of low-lying land away from people and property - flood plains - to flood, and then to slowly release water afterwards.  This reduces the height of a river in flood.  In Sussex there are now many examples of landowners doing woodland planting, washland creation and river re-naturalisation (such as putting back meanders and allowing rivers to merge with their flood plains) to reduce flood risk and to deliver other public benefits.  This is done because of the careful thought and good will of the landowners involved, with a small amount of financial help from incentive packages.  What is needed is good government policy and financial packages to enable this to happen in a planned and strategic way. Oh – and by the way, all this is good for wildlife too. 

There is a place for dredging and engineered hard defences, but these have to be part of a far more sophisticated approach to managing flooding across the whole river catchment.

Does this all sound expensive?  In truth it is expensive not to manage our catchments in a more sophisticated and naturalistic way.  A study in the West County calculated the costs of such naturalistic catchment management against the financial returns in terms of reduced flood risk and other benefits.  The result was a 65:1 return on investment!  A cost of £1 delivered £65 worth of benefit.  Bad catchment management is not £1 saved, it is £65 spent!  At present it is hard for farmers and landowners to gain the funding – even stay in business – by allowing flood plains to flood and deliver these public benefits.  This is ludicrous.  It should be easy, even lucrative, for a landowner to have the opportunity to manage catchments in a positive way.

The sad thing is that this is not even new.  They have taken this approach in The Netherlands for decades and here the Environment Agency moved to this approach many years ago.  A media frenzy, backed up by a lack of support by government for its own agencies could, however, throw us back into the dark ages.

Flood management is not a balance of wildlife versus people, as was implied to the Environment Agency’s CEO recently. Currently both people and wildlife are struggling with an antiquated approach to flood management which has left a legacy of poorly planned infrastructure, too much urban surface water run-off and over-drained landscapes which flood too easily.  In the past we have chosen badly, perhaps we can make better choices for the future.

No comments: