At the end of 2020, The Environment Agency declared that 5.2 million homes and businesses across England are at risk of flooding, that’s one in every six properties. Roughly half of these are at risk of flooding from rivers or the sea, whilst the other half are at risk of surface water flooding. Ian Paton, Head of Oxford PBC and Ed Yeates, Project Engineer at Property Consultants Cluttons, discuss how climate change is increasing the risk of flooding to UK property owners and why implementing flood risk management measure is crucial to protecting assets.
Causes of flooding in the UK
In the UK coastal flooding has been regarded as the second highest risk of civil emergency after pandemic influenza, with an estimated £150 billion of assets at risk.
Fluvial (river) flooding is mainly caused by excessive rainfall or heavy snow melting upriver, leading to high water levels downriver overflowing the river’s edges. When this occurs simultaneously with extreme coastal water levels, flood levels can be particularly high. This combination of coastal and fluvial flooding is termed compound flooding and can bring detrimental consequences to both coastal and inland towns.
Impacts of climate change on flooding
Excessive rainfall events are a direct consequence of climate change, which is warming the earth’s atmosphere and increasing its capacity to hold moisture. As such, scientists are predicting the UK will receive around 10 percent more rainfall per year by 2100, compared to 1986-2005. We are already seeing the impacts of climate change on rainfall in the UK. Between 2000 and 2014, 45 percent of rainfall records were broken in terms of wettest year, wettest period and wettest months on record.
This increase in rainfall, combined with rising sea levels, suggests the frequency and severity of flooding in the UK will rise significantly over the coming years. We must have effective resilience measures in place to withstand the impacts of such events. Defra estimated the economic damages from the 2013/2014 floods were in the region of £1 billion to £1.5 billion, with 46 percent of this allocated to homeowners and businesses. It is clear that the measures the UK had in place at this time were not enough to protect assets and reduce the knock-on effects to other parts of society. If significant investment and a more holistic approach to flood risk management is not in place over the coming years, the consequences of future flooding will be difficult to recover from.
The UK government’s response
The UK Government announced in July 2020 a new £5.2 billion investment for building new flood defences to better protect 336,000 properties in England by 2027.There is no question that this is a step in the right direction with regards to investment into flood risk management, but in order to cope with the long-term projections of flooding, the risk must also be managed at catchment level – before the flood reaches the property.
In an attempt to provide some structure to future investments, the UK Government has placed a statutory duty on the Environment Agency (EA) to develop, maintain, apply and monitor a national flood and coastal erosion risk management strategy. This document was first published in 2011 but revised in July 2020 with an Action Plan to follow in April 2021 detailing how this will be implemented over the coming years.
It is estimated that for every £1 spent on protecting properties against flooding, £5 in damages are avoided. However, this does not consider the fact that floods are becoming more severe and frequent. Over the next few decades, with the impacts of climate change and the demand for new properties to be built on floodplains, the level of investment and choice of resilience measures seen in the past decade will not be enough. A shift towards catchment management and ensuring communities can recover quickly from floods is paramount. The Environment Agency’s strategy recognises this and provides the following actions to be implemented alongside traditional flood defences:
- Avoiding inappropriate development in the floodplain.
- Making greater use of nature-based solutions that take a catchment led approach to slow the flow of or store flood waters to improve resilience to both floods and droughts.
- However, this would require large changes in current agricultural practices to move away from intensive farming methods which lead to the soil becoming compacted and in turn restricts percolation of rainwater and contributes to local surface water flooding.
- Better preparing and responding to flood and coastal incidents through timely and effective forecasting, warning and evacuation.
- Helping communities and local economies recover more quickly after a flood or ‘building back better’.
- Making properties and infrastructure more resilient to future flooding.
Infrastructure resilience
As part of the strategy, emphasis is placed on building resilient infrastructure and ‘building back better’ when replacing or refurbishing current assets. Infrastructure has a particular importance with regards to flood resilience due to the significant knock-on effects to other businesses and livelihoods when disruptions happen. Recent floods have highlighted the vulnerability of critical infrastructure in the UK and the economic damage that flooding causes when effective resilience measures are not in place.
Over two-thirds of properties in England are dependent on infrastructure sites and networks located in flood risk zones. In order to cope with the projected rise in flood severity over the coming years, we must put infrastructure resilience at the forefront of flood risk management. The EA’s strategy supports this in setting an objective for risk management authorities to work alongside infrastructure providers to ensure resilience is built into future investments. It will be interesting to see how the 2021 Action Plan suggests this resilience is achieved, given the various constraints and limitations that often come with infrastructure developments.
Summary
The recent investment and strategy provided by the UK Government is a positive step and has recognised the additional broader range of resilience measures required to combat the impacts of climate change on flooding. Yet, this is merely the start of the journey, and for the value of the strategy to be realised it must be implemented effectively – through stakeholder consultation and educating asset owners to the risks they face.
The impact that climate change is having on flood risk in the UK is devastating and we must move from mitigative to adaptive measures in order to withstand the impacts of flooding in the coming years. How we do this, and exactly which adaptive measures are chosen, will have a massive impact on the degree of resilience achieved.
