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Similar to other geohazards, floods are unpredictable and complex. This makes preparing for them challenging especially for communities that deal with unexpected or unforeseen flood events that may occur. Flooding is an interesting case study for understanding how geohazards and society interact which can have disastrous consequences if little preparation is made in advance. As far as floods in society are concerned they are usually understood in terms of risk, such as the likelihood that someone’s home or business may be flooded.
If the flood risk is low perhaps little is done to mitigate flooding. In some situations insurance can be purchased to cover extreme events if they should happen, but little is done overall. If the risk is perceived as high or of concern to an individual, community, county or nation, then usually flood mitigation efforts, including research, should be prioritised. If flood risk is high it begs the question why is this the case? This comes down to exposure and vulnerability.
If property or people themselves are exposed to the flood hazard, with little to no flood protection, they are at risk of losing their home, business, livelihood, way of life or even their lives. But better ways of identifying flood vulnerability are needed to help make communities resilient to flood hazards.
Professor Alberto Montanari from the University of Bologna visited IHRR recently to give a seminar on the damages and fatalities caused by flooding that has been increasing in countries throughout the world. As a hydrologist, a scientist who studies the movement, distribution and quality of water, he presented some of his recent work in identifying areas of flood vulnerability in Italy. He said ‘that flood vulnerability and frequency are intimately connected’, which includes the effects of climate change and other factors that affect flooding, such as land use. Read the rest of this entry »
10th March 2014, 13:00 to 14:00, Seminar Room 010, Dept of Geography, Professor Alberto Montanari, University of Bologna, Italy
The damages and fatalities caused by floods are dramatically increasing in many countries of the world, including in Europe and developing regions. Scientists have long investigated the possible reasons for the raising severity of floods, in order to devise efficient strategies for mitigating the above damages. There is a general consensus that is widely amplified by media, that climate change is the most important triggering factor of the increased flood hazard and vulnerability. This seminar will give an overview of recent research on this subject and will provide a forward-looking perspective on the impact of floods on human activity. Read the rest of this entry »
A satellite view of the floods at Somerset Levels as heavy rains earlier this month brought severe flooding to South West England. This comes at a time when extreme weather events have become more frequent throughout the world, particularly rainfall. In order to prepare for such events finding ways to adapt built infrastructure and coordinate services across the public and private sectors is vital.
Extreme rainfall in southern England
Southern England is currently undergoing an extraordinary period of exceptional rainfall, especially in the south, which is causing floods on an unprecedented scale. This rainfall, which is likely to be a consequence of climate change, shows no signs of abating, with further heavy falls expected over the next few days. Not surprisingly there have been many landslides, especially on the coast and along railway lines, and more can be expected. The UK Met Office provides monthly precipitation data for Southern England . I have downloaded the data and plotted the monthly time series from 1910 (the start of the dataset):
The horizontal line in the long-term mean value (77.3 mm). The 2014 total, at 165.4 mm, is 2.8 standard deviations from the mean – a truly exceptional value. And of course it is still raining, such that since the end of January the floods have got much, much worse. Read the rest of this entry »
Over the last few days Central China has been experiencing exceptionally heavy monsoon rainfall, causing very high levels of damage. The TRMM data for landslide potential for the last seven days of rainfall highlights the areas considered likely to be affected by landslides (and note that there are also substantial parts of N. India and Nepal that are experiencing problems:
Unfortunately, the worst of the rainfall appears to have affected the areas struck by the 2008 Wenchuan earthquake in Sichuan Province. This is a zone that remains very vulnerable to landslides because of the legacy of the seismic even, compounded by inappropriate development in the rush to rebuild after the earthquake. The effects have been disastrous. The largest impact to date is the landslide at Sanxi in the area administered by Dujiangyan City, which is reported to have killed 12 people whilst a further 11 are missing, with very limited chances of survival. The landslide is reportedly very large, with a travel distance of 2 km and a volume of 1.5 million cubic metres. Read the rest of this entry »
From 2001-10 there have been unprecedented extremes in global climate with more national temperature records broken than in any previous decade, according to a recent report from the World Meteorological Organization. For many this may not seem like news, it has been known for some time that the planet’s climate(s) has been changing radically for some years. Even people in their everyday lives are able to perceive with some accuracy changes in climate. What the report highlights is that these extremes have worsened in recent years, especially in regards to their impacts on human life and economy. During 2001-10 more than 370,000 people died as a result of extreme weather and climate conditions. This includes heat waves, floods, cold snaps, drought and storms.
Is every extreme weather event due to a changing climate? This is something that requires further research because of the complexities involved. What researchers can say is that it’s more likely for extreme weather events such as heat waves to occur more frequently because of climate change, and with increased intensity. This makes planning challenging, nevertheless it needs to happen. People can learn from extreme weather events that have taken place around the world in order to plan for the present and future. Climate adaptation, while less attractive in some cases to mitigation and more recently geoengineering techniques, has a major role to play in mitigating the impacts of extreme weather events. Read the rest of this entry »
On Thursday morning, there was a knock on my office door – “The BBC wants to talk to someone about snowmen” – “okay…” I reply, not quite sure where this is going. Five minutes later I am on the phone to a reporter.
It had been in the newspaper that morning about reducing flood risk by building snowmen. The Environment Agency was concerned about a rapid warming in the weather melting the snow and this released water creating a flood risk. The proposed solution from the Environment Agency was based on the fact that snow in large piles, either stacked up or as a snowman, takes longer to melt and hence would slow the delivery of the water to the rivers (see BBC News article). My first thought on this was that we would need to build a huge number of snowmen to capture enough water to have an effect. Having travelled from Durham to London and back this week, it was clear how much of the country was covered in snow. I was about to calculate the number of snowmen required to capture a significant fraction of the water (Prof. Kevin Hiscock at UEA has done this for the River Wensum catchment and estimated 6 million snowmen in that area alone) before I started to think about the problem from another perspective.
The heavy rains that hit the North East of England recently caused some major floods in the last few days. Regions of the A1 motorway were shutdown for two days between Disforth (North Yorkshire) and Bradbury (near Durham). People’s homes and businesses were also flooded in Morpeth and other cities, towns and villages in the North East due to heavy rain fall. According to BBC News, among the areas worst hit by flooding were Morpeth, Durham, Rothbury, Chester-le-Street and Stockton-on-Tees.
Some of the water levels (hydrographs) recorded by the Environment Agency show the level above previous records, while in other parts it seems to have returned to previous levels. This morning the River Swale in Yorkshire a major tributary of the River Ure which becomes the River Ouse (which caused major flooding in Yorkshire) was measured at 5.28 metres at Crakehill close to the record of 5.45. Read more
IHRR was very pleased to welcome Prof Sue Kieffer from the University of Illinois At Urbana-Champaign as a COFUND Senior Research Fellow. During her time in the Institute, Sue researched highly energetic geologic events, particularly comparing and contrasting the behaviour of torrential river floods with that of large landslides. Sue is one of the world’s leading authorities on geological fluid dynamics that addresses dynamic surface processes, such as movement of water and wind and the dynamics of volcanic eruptions and meteorite impacts. Her work has made a large impact on the geosciences, especially understanding the geologic processes that lead to different kinds of hazards, such as floods and landslides. Sue’s research spans terrestrial as well as extraterrestrial environments as her geyser theory developed early in her academic career was applied to the study of volcanoes on Io, one of Jupiter’s moons. Also, her shock wave theory was used to study the historic eruption of Mt St Helens and the massive flood on the Colorado River in 1983. Read more
Dr David Milledge and Prof Stuart Lane present the results of a recent study they authored on flood prevention in the Yorkshire Dales located in Northern England that investigates the role of controlling surface drains (grips) to manage flood risk.
The moorlands of large swathes of Upland Britain are covered by hundreds of kilometres of surface drains or ‘grips’. These grips were originally dug between the 1950s and the 1970s to dry out the peat soil with the expectation that this would improve the vegetation for grazing and game. Grips have dried out the peat, but ‘gripping’ has since been associated with a range of negative impacts both in the moors and in the rivers that flow from them. Drying the peat both changes the ecosystem that it sustains and makes it more susceptible to erosion. This eroded peat is then transported downstream and needs to be removed from the water before we can drink it. Read more