Flood adaptation and mitigation - What are the key solutions?

Floods have been devastating parts of Europe and the east coast of America to name but two parts of the world over the last month. It has brought to the front of our minds the need to protect human habitation from the increasing number and severity of such events.

The Independent Panel on Climate Change official report states that global average sealevel rises over the next century could be as much as 3 feet on business as usual and given the amount of greenhouse gases currently in the atmosphere. But some scientific evidence supports even higher numbers, five feet and beyond in the worst case.

The East Coast of the United States will experience rises higher than average because the land is sinking at the same time. Tide gauges along the East Coast show an average rise of 1.5 inches per decade.

As a result, towns like Norfolk in Virginia are having to spend millions on raising streets and improving drainage to cope with routine flooding.



Floods in Pisa, Italy.

Wild weather has been experienced along the East Coast of the United States of America since Christmas. But the flooding risks are not confined to America. Severe storms and flooding have also been affecting Europe:

• areas of Italy and France are on flood alert as heavy rain brings chaos to parts of Europe. Hundreds of people were forced to evacuate their homes in the Italian city of Pisa as the Arno river threatened to burst its banks on Friday;
• two people have died and more than 150 people have been airlifted to safety following floods in south-eastern France;
• high seas are causing widespread flooding along France's and the UK and Ireland's Atlantic coast;
• facing flood risk is the most immediate of problems to be tackled by an Inter-American Development Bank (IDB) loan to the Trinidad and Tobago Government;
• parts of England such as the Somerset levels have been underwater since Christmas.

At the same time as flooding is causing massive devastation in the UK, the government is cutting back on spending on flood risk mitigation and adaptation. This decision has been lambasted by the UK's Chartered Institution of Water & Environmental Management, which has called for Government funding for flood and coastal erosion risk management (FCERM) to be extended instead.

It says: "funding is crucial not only to mitigate the impacts of flooding, but also to educate the population about the impacts of climate change," and "for maintenance activities alongside capital improvements to prolong the life of existing flood and coastal defences and also ensure floodwaters are conveyed through the land drainage network". These lessons apply everywhere.

Many issues are at stake here but it's not just about pouring concrete.

Scientific knowledge says that flooding can be reduced by planting trees in the uplands and yet many government policies support the continued removal of trees and forestry in these areas and replacing them with monoculture agricultural practices.

Amidst raging public controversy in Britain over the recent flooding environmentalist George Monbiot has pointed out a research paper on upland reforestation practice which estimates that if all the farmers in a catchment area reforested just 5% of their land, "flooding peaks downstream would be reduced by about 29%. Full reforestation would reduce the peaks by about 50%".

Further down the catchment area, in the foothills and lowlands, different agricultural practices affect the risk of flooding, such as, Monbiot  says: "the misuse of heavy machinery, overstocking with animals and other forms of bad management [that] can – by compacting the soil – increase the rates of instant run-off from 2% of all the rain that falls on the land to 60%."

To these findings a new risk is highlighted by a new study published in Hydrological Sciences Journal, which examines the key reasons for increasing frequency and severity of floods. The authors combine the outcomes of the IPCC Special Report on “Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation” (SREX report) with more recent research to give a rounded view of the cost of flooding (both human and material), the causes of increased flood risk and predictions of future global flooding patterns.

These show a clear link between population density and flooding. Currently 800 million humans are living in areas vulnerable to flooding. This is predicted to rise by a further 140 million during 21st century as we see continued economic and population growth.

So at the same time as a reduction of woodland, changing river flow and the urbanisation of flood plains, we are continuing to exacerbate global warming, raise sea levels and destroy wetlands, particularly in coastal areas, which also help to absorb storm surges.

It seems like the perfect storm, an unparalleled combination of exactly the wrong policies and practices if we want to reduce the risk of flooding, not just of coastal settlements but inland ones also.

What are the correct policies, then? This is the subject of an exclusive webinar to be held on the Sustainable Cities Collective website on Monday 10th of February at 12 PM Eastern Standard Time. Register here.

The participants will include:

• Natasa Manojlovic is a senior researcher at the Institute of River & Coastal Engineering (TUHH) and is a visiting researcher at the UNESCO-IHE in Delft, NL. Her research and teaching is focused on flood risk management (flood resilient technology, systems, tools and strategies as well as capacity building of stakeholders- phD research), environmental hydraulic engineering a with the scientific research directed to urban hydrology.

• Thomas Colbert, AIA, an Associate Professor at the University of Houston. His research concerns the preparation and evaluation of architectural and planning responses to the threat of climate change and extreme weather events impacting the Texas-Louisiana Gulf Coast. Prof. Colbert holds degrees from Princeton University and the University of Cambridge.

• Paul O'Hare, is a Lecturer in Geography and Development at Manchester Metropolitan University. His primary research interest revolves around efforts to engage ‘the public’ in governance and planning decision-making processes. Previous research has been funded by the European Union (SMARTeST EU Flood Resilience Project), RCUK (Re-Design) and the ESRC (PhD). His most recent work in the EUFP7 SMARTesT project (led by the Building Research Establishment) examined social, economic and cultural issues regarding the use of property level protection for flood risk management.

You can register for the webcast here.