Climate Change Won’t Wait for Widespread SuDS

Written By: Market Development Director, Hydro International.

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The Government’s advisory committee on climate change has issued a strong warning that we must do more to improve our flood resilience as changing weather patterns result in rising sea levels, increased flooding and greater swings between storms and droughts.

Of all the consequences of changing weather, increased flood risk poses the greatest threat, according to the Committee on Climate Change, the body that exists to provide independent, evidence-based advice on climate change resilience to the UK Government and Parliament.

Last winter, parts of England saw rainfall unprecedented in 250 years of records. In January some areas saw rainfall three times the average and 7000 properties were flooded. The damage done could have been much worse without investment already made in flood protection and emergency planning.

Yet, our memories are short when it comes to paying for flood defences. True, the Government pledged £270million after the winter floods, but only to repair the damage already done. Funding shortages mean three-quarters of our existing flood defences are inadequately maintained, according to Managing Climate Risks to Well Being and the Economy 2014, (July, 2014).

Yet every £1 invested in flood defences in the UK has been calculated to save £8 in flood damage. There have been improvements in flood resilience in recent years, but not enough says the CCC.

Just seven years ago another flooding ‘wake-up call’ prompted a major review of the country’s flood resilience. The Pitt Review recommended a raft of measures that led to the 2010 Flood and Water Management Act in England and Wales. But some important parts of the Act are still to be implemented. The CCC wants the Government to evaluate whether the local flood risk arrangements have been made in line with the Pitt recommendations, warning that some of the funding provided by Defra to Lead Local Flood Authorities is being diverted to other council services.

New regulations to make Sustainable Drainage Systems (SuDS) compulsory in England and Wales have been delayed repeatedly and are still to be implemented. (See my blog “SuDS Implementation Delayed Again”).

But here is a sobering fact: Even if the legislation is in force and the phased implementation completed over the next few years, the flood-resilience contribution made by SuDS through new developments will be a tiny fraction of what is needed.

The real challenge comes in upgrading and improving the existing surface water drainage infrastructure. Because they are often smaller, and less grandiose compared with new developments, retrofit SuDS schemes can seem like a poor relation. But in reality, they are the lifeblood of improving surface water flooding resilience and water quality.

Whilst the Flood and Water Management Act has tended to draw our focus to new residential developments, SuDS also need to be implemented to ensure flood and water quality resilience from industrial and commercial premises, especially where a high degree of pollution control is also required. Click here for more retrofit SuDs examples.

Critically, to work, the principle of attenuation at source must be applied at a micro and a macro level. Whilst small scale retrofit schemes and new development SuDS deal with water quality and quantity at the local level, larger scale flood alleviation schemes are also needed to hold back water in the upper reaches of rivers.

The committee placed great emphasis on the need for a more comprehensive approach to flood resilience that recognises the water is part of a wider energy and transport infrastructure. It’s also critical that we start to view water management in a more ‘joined-up’ way and here approaches such as Water Sensitive Urban Design can provide clues to managing water in a more integrated way.

Using the same SuDS principles of attenuation at catchment level is also a critical part of the water management jigsaw. Schemes that hold back water in the upper reaches of a river provide sustainable means of protecting urban centres. To achieve good catchment management requires and overall planning and management approach which involves a number of agencies including water companies, local authorities and the Environment Agency is the key to success.

As Climate Change continues to gather momentum, there is still a huge amount to be done.

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