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Flood Defence (flood + defence)

Distribution by Scientific Domains

Earth and Environmental Science	50%

Selected Abstracts

Fish utilisation of managed realignments

FISHERIES MANAGEMENT & ECOLOGY, Issue 6 2005
S. COLCLOUGH
Abstract, One area of ecological benefit not yet fully evaluated in European waters is the utilisation of restored saltmarsh habitats by fish species. This study examines the utilisation of managed realignments and relic saltmarsh by fish species. Factors affecting habitat heterogeneity and fish populations are discussed, and recommendations are made with respect to scheme design and management that will maximise the biological and socio-economic values. Fish populations in the high intertidal areas were assessed using a suite of techniques, including observations on feeding behaviour. Each microhabitat was discussed as a function of the extent of fish colonisation. A positive relationship between the degree of fish utilisation and habitat heterogeneity was ascertained using species richness, abundance and behavioural observations. This study will aid habitat valuation for economic justification of managed realignments, over and above existing drivers, such as compensatory habitat for encroachment, flood defence and the European Union Habitats Directive. The work now forms part of a wider European Interreg IIIb project, COMCOAST. [source]

Characteristics of river floods and flooding: a global overview, 1985,2003,,

IRRIGATION AND DRAINAGE, Issue S1 2006
Klaas-Jan Douben
inondation; victims; dommages; stratégies de protection contre les inundations Abstract Since ancient times people have settled in flood-prone areas due to favourable geographic conditions which facilitate economic growth, such as accessibility (transportation) and food production (fertile land). This fact forces societies all over the world to protect valuable assets against flooding. Nevertheless flooding is still the most damaging of all natural disasters. One-third of the annual natural disasters and economic losses and more than half of all victims are flood related. Flood mitigation policies and measures have been implemented, enabling societies to increase their resilience to flood hazards. With increasing population densities, often associated with improved living standards and consequently higher values of property and infrastructure, flood defence receives more importance and the consequences of flooding become less acceptable. Trends in flood frequencies and flooding damage seem to be increasing, primarily due to a growing vulnerability arising from societal changes such as interference by occupation, developments, investments and land-use changes in flood-prone areas. The Asian continent was particularly affected by floods and flooding between 1985 and 2003. It recorded nearly half of all flooding events; together with Europe and North America it was confronted with the majority of flooding damage and it incurred nearly three-quarters of all casualties. Copyright © 2006 John Wiley & Sons, Ltd. Depuis toujours les populations se sont installées dans les zones à risque d'inondation du fait de conditions géographiques favorables à la croissance économique, telles que l'accessibilité (transport) et la production de nourriture (terre fertile). Ceci oblige les sociétés partout dans le monde à protéger les biens contre les inondations. Mais celles-ci sont toujours les plus préjudiciables de tous les désastres naturels. Chaque année, un tiers des désastres naturels et des dommages économiques ainsi que plus de la moitié des victimes sont liés aux inondations. Des politiques et des actions de protection contre les inondations ont été mises en oeuvre, permettant aux sociétés d'augmenter leur résistivité aux risques d'inondation. Avec l'augmentation des densités de population, souvent liée à la progression des niveaux de vie et donc à la valeur plus élevée des habitations et des infrastructures, la protection contre les inondations devient plus importante et leurs conséquences moins acceptables. La fréquence des inondations et de leurs dommages semble en augmentation, principalement en raison d'une vulnérabilité croissante résultant de changements sociaux tels que les interférences des activités, aménagements, investissements et occupation de l'espace dans les zones à risque. Le continent asiatique a été particulièrement affecté entre 1985 et 2003. Il a enregistré presque la moitié de tous les événements d'inondation, a dû faire face à la majorité des dommages avec l'Europe et l'Amérique du Nord et a compté presque trois quarts de toutes les victimes. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Flood risk management and planning policy in a time of policy transition: the case of the Wapshott Road Planning Inquiry, Surrey, England

JOURNAL OF FLOOD RISK MANAGEMENT, Issue 3 2009
S. Tunstall
Abstract This paper focuses on an English case study example of decision making on development and flood risk. It was carried out through qualitative document analysis and 13 in-depth interviews with flood risk professionals and others in the Lower Thames Valley. It illustrates the recent shift in policy in England from flood defence to a flood risk management approach with an increased emphasis on spatial planning and development control. It shows that decision makers take time to come to terms with new government policy. Despite the more prescriptive government guidance on development and flood risk in Planning Policy Guidance 25 and later documents, there remains scope for disagreements, for example, over what constitutes ,safe' development in flood risk areas. Other sustainability objectives can still weigh heavily against flood risk in local decision making. The potential contributions of modelling, and new visualisation techniques in the flood risk management and planning context are considered. [source]

A regional frequency analysis of United Kingdom extreme rainfall from 1961 to 2000

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 11 2003
H. J. Fowler
Abstract Multi-day rainfall events are an important cause of recent severe flooding in the UK, and any change in the magnitude of such events may have severe impacts upon urban structures such as dams, urban drainage systems and flood defences and cause failures to occur. Regional pooling of 1-, 2-, 5- and 10-day annual maxima for 1961 to 2000 from 204 sites across the UK is used in a standard regional frequency analysis to produce generalized extreme value growth curves for long return-period rainfall events for each of nine defined climatological regions. Temporal changes in 1-, 2-, 5- and 10-day annual maxima are examined with L-moments using both a 10 year moving window and the fixed decades of 1961,70, 1971,80, 1981,90 and 1991,2000. A bootstrap technique is then used to assess uncertainty in the fitted decadal growth curves and to identify significant trends in both distribution parameters and quantile estimates. There has been a two-part change in extreme rainfall event occurrence across the UK from 1961 to 2000. Little change is observed at 1 and 2 days duration, but significant decadal-level changes are seen in 5- and 10-day events in many regions. In the south of the UK, growth curves have flattened and 5- and 10-day annual maxima have decreased during the 1990s. However, in the north, the 10-day growth curve has steepened and annual maxima have risen during the 1990s. This is particularly evident in Scotland. The 50 year event in Scotland during 1961,90 has become an 8-year, 11-year and 25-year event in the East, South and North Scotland pooling regions respectively during the 1990s. In northern England the average recurrence interval has also halved. This may have severe implications for design and planning practices in flood control. Copyright © 2003 Royal Meteorological Society [source]