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Flooding - we can't build ever-higher walls!
06 Jan 2016 11:44     A+ | a-
The householder stoically pointed to the level, on her living room wall, of last week's floods - just above head height. Then she indicated the then record flooding level in 2005 - around waist height.

Things are clearly getting worse, and the effects of climate change are living up to the predictions that scientists have been making for at least a decade - principally of more extreme weather events driven by increased warmth in the atmosphere.

Time for a Review?

Collectively, we - and particularly the highest levels of government - have known for years that this was coming, and have chosen to ignore its potential to tear communities and local economies apart. In much the same way as WW1, 'The War to end all Wars', patently failed to end all wars, we appear to have learnt little from the devastating 2007 floods.

The 2008 Pitt Review was set up to seek answers, to prevent such events happening again. To some extent it was successful in doing so, resulting in the 2010 Flood and Water Management Act (FWMA), which made specific provision for Sustainable Drainage Systems (SuDS).  In particular, Schedule 3 set out to overcome the long-standing barrier to SuDS implementation, that of adoption and maintenance of SuDS systems. It also aimed to make SuDS a mandatory part of the planning process for all new developments.
During the course of the coalition government (2010-2014) Schedule 3 was consulted, delayed and dissipated, until finally, at the start of 2015, it was completely neutered, and any pretence at making meaningful provision for SuDs adoption was dropped.  In an effort to abolish any 'hindrances' to house building, SuDS would not be required for developments of less than 10 houses, and in any case, only where "reasonably practical".  This is a great get-out clause for unwilling developers, but is inconsistent with the best industry knowledge - that there is no reason why SuDS should not be the norm for developments - see below.
As we think about Appleby, Carlisle, York and Calderdale - this year's principal targets - we should remind ourselves of other major flooding events: in Somerset and Southern England during Jan-Feb 2014; Cumbria in 2009; Gloucestershire and South and East Yorkshire in 2007; Cumbria again in 2005; and Boscastle in 2004.  In addition there have been many other serious events across the UK, with riverside towns, such as Morpeth and York, often being worst-hit. 

Image: Rescue team boat on the street. 2015 Floods in York, corner of Huntington Road and Park Grove (with thanks to resident, Bea Thackeray)

The government's standard response is to build ever higher walls and defences. Whilst these are partially effective, they can be, and are being, over-topped. We have to ask, can we keep building ever-higher walls to separate us from our rivers?  What if it rains on the 'wrong side' of the wall? Are we willing to accept the potentially ugly and divisive effect of flood barriers on our river banks?
So what else might we be able to do?  Three main things:
  • SuDS on new developments
  • Retrofit SuDS
  • Catchment scale land management


One wonders how bad things have to get before the government realises that this year's economic growth targets cannot outweigh the need to develop sustainably for future generations. SuDS should simply be standard for all new developments. 

As the 2015 CIRIA SuDS Manual states,

"Provided that drainage is considered early enough in the outline design of a new development then there is no reason why SuDS should not become the norm everywhere.... Where SuDs are designed to make efficient use of the space available, they can often cost less to implement than underground piped systems ".

SuDS Basin at Manor Park Sheffield (with thanks to Roger Nowell at SCC)
Image: SuDS Basin at Manor Park, Sheffield (with thanks to Roger Nowell at Sheffield City Council)

Retrofit SuDS

Whilst it is vital to embed SuDS in all new developments, 80% of the buildings (and therefore their surroundings) which will be in use in 2050, are already built. 

If we only fit SuDS to new developments, we can only deal with, at best,  20% of the building stock likely to be in use in 2050 - by which time climate change effects will be far more serious.  These effects are already overwhelming existing settlements and their communities. We have to build resilience into our existing building stock, by re-purposing largely redundant open space and verges for short-term, but large-scale, water attenuation during storm events.

Done well, this can also have multiple benefits of creating more beautiful, less mundane, places to live, as well as improving biodiversity.  In turn, this provides health benefits, through increased outdoor activity, and improved air and water quality. The list of potential benefits is big enough to fill an article all by itself. (Susdrain 'why retrofit?')

Catchment Scale Land Management

When rain falls on the Lake District or the Pennines or the Peak District, and towns downstream flood, there is a limit to the contribution that SuDS can make. The water causing the rivers to overtop has been shed too rapidly from drained moorland and heavily-grazed and trampled fields. Drains and rivers are cleared to encourage rapid runoff, with almost inevitable consequences as the water collects and is channelled through downstream towns. 

Water can be held back: the natural drainage principles of SuDS can apply as well to large rural areas as they do to small urban areas.  'Making Space for Water' is a long-established phrase, one that was often heard but little acted upon in the UK during the 2000's; whilst Dutch cities like Nijmegen on the Waal (Rhine) undertook major planning, landscape and engineering works in their 'Room for the River' project to deal with what they saw as inevitable - the need to live with greater variation in water flows - both flood and drought. 

The ability of trees, and particularly woodland, to hold back storm water and improve infiltration of rain into ground water and aquifers, is well-known. But we have tended to question and play with the theory, rather than getting on and looking at land holistically - as something other than just a food factory.

A Suite of Solutions

There is no question that we need 'hard' flood defences to help contain rising waters from rivers and surges from the sea. But the compelling evidence of the importance of 'soft' defences, like SuDS, water-sensitive land management and Making Space for Water, has been sidelined for too long. 

Soft defences - green infrastructure rather than grey infrastructure - are often highly cost-effective and multi-functional.  Preoccupation with easing the way for economic growth is understandable, but is a very selective and dangerously blinkered view of a much larger picture - one in which the effects of climate change will become increasingly hard to ignore. 

The economic cost of flooding (£3-4 billion in the 2007 floods alone, with estimates of £5 billion for this winter's flooding - to date) should be sufficient economic evidence that we need a new approach, one which contains a suite of solutions including comprehensive SuDS, land management and flood defences. Otherwise, the cost to communities will be far more than just economic.

The stoic three-times flood victim, on the evening news, can only hold out for so long. The implementation of a broader, more effective set of solutions is urgently required and long overdue.
By Bill Blackledge CMLI
member of LI Technical Committee
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