Flash floods are characterized by their suddenness, fast and violent movement, rarity, small scale but high level of damage. They are particularly difficult to forecast accurately and there is little lead time for warning. This makes motorists especially vulnerable. Assuming that these flash flood hazard specificities may be the significant factors leading to difficulties for drivers to perceive danger, we used cognitive mapping combined with GIS data processing to assess motorists’ flash flood risk perception on their daily itineraries. The analysis of 200 mental maps collected allows planners to have maps highlighting dangerous areas where risk perception is weak and to identify reasons for this. 相似文献
ABSTRACT: Clearcutting aspen from the upland portion of an upland peatland watershed in north central Minnesota caused snowmelt peak discharge to increase 11 to 143 percent. Rainfall peak discharge size increased as much as 250 percent during the first two years after clearcutting, then decreased toward precutting levels in subsequent years. Storm flow volumes from rain during the first two years increased as much as 170 percent but declined to preharvest volumes in the third year. Snowmelt volumes did not significantly change. Snowmelt peak discharge occurred about four to five days earlier after clearcutting, but the timing of storm flow from rainfall was not changed. Snowmelt peaks remained above precut size for nine years after clearcutting on an area undergoing natural regeneration to aspen saplings. Partial cutting - up to approximately one-half of the watershed - reduced peak snowmelt discharge because melt was desynchronized in cleared and forested parts. Clearing more than 2/3 of the watershed caused snowmelt flood peak size to double during years with snow packs in excess of seven inches of water that remained until a day when maximum air temperatures exceeded 60d?F. 相似文献
Probability distributions that model the return periods of flood characteristics derived from partial duration series are proposed and tested in the Fraser River catchment of British Columbia. Theoretical distributions describing the magnitude, duration, frequency and timing of floods are found to provide a goof fit to the observed data. The five estimated parameters summarizing the flood characteristics of each basin are entered into a discriminant analysis procedure to establish flood regions. Three regions were identified, each displaying flood behavior closely related to the physical conditions of the catchment. Within each region, regression equations are obtained between parameter values and basin climatic and physiographic variables. These equations provide a satisfactory prediction of flood parameters and this allows the estimation of a comprehensive set of flood characteristics for areas with sparse hydrologic information. 相似文献
ABSTRACT: In order to promote a uniform and consistent approach for floodflow frequency studies, the U.S. Water Resources Council has recommended the use of the log-Pearson type III distribution with a generalized skew coefficient. This paper investigates various methods of determining generalized skew coefficients. A new method is introduced that determines generalized skew coefficients using a weighting procedure based upon the variance of regional (map) skew coefficients and the variance of sample skew coefficients. The variance of skew derived from sample data is determined using either of two non-parametric methods called the jackknife or bootstrap. Applications of the new weighting procedure are presented along with an experimental study to test various weighting procedures to derive generalized skew coefficients. 相似文献
After a disaster, the media typically focus on who is to blame. However, relatively little is known about how the narrative of blame plays out in media coverage of the release of official disaster reports. This paper examines coverage by two Australian newspapers (The Courier‐Mail and The Australian) of the release of the Queensland Floods Commission of Inquiry's Interim Report and its Final Report to identify whether and how the news frame of blame was used. Given the absence of blame in the Final Report, the newspapers resorted to the frame of ‘failure’ in news and feature articles, while continuing to raise questions in editorials and opinion pieces about who was to blame. This study argues that situating coverage of the report within the news frame of failure and questioning who was to blame for the disaster limited the media's ability to facilitate a discussion about the prevention of similar disasters in the future. 相似文献
This article discusses inter and post-war works of fiction written by Polish and German-speaking authors with biographical connections to Oder River regions. The literary texts provide insights into the vulnerability to and resilience constructions of floods, which are related to such cultural factors as migrant histories and traditions, regional beliefs and religion, and the political background of changing frontiers in 1919 and 1945 that affected residents of this cross-border area.
The capacity to cope with the flooding Oder, especially after the major flood in 1997, intertwines with the problematic Polish-German relationship, including Silesia. For Polish communities, whose environmental cultures have been distorted by wars, resettlement and communism, vulnerability and resilience perceptions lack representations of the tangible river. It is culturally bounded in the stigmatising image of the Oder as the border of division, revived after 1945 and exposed by the Polish communist party in the so-called ‘Polonisation’ of the ‘Recovered Territories’. Fiction detects the problem of overworking the difficult past in response to the Oder’s hazardous nature. Writers representing an emotional attachment to the river and an aquacritical approach express the need to learn about the river’s lively nature, both in cooperating and sharing space, which is called the environmental adaptation. 相似文献
This paper explores how social networks and bonds within and across organisations shape disaster operations and strategies. Local government disaster training exercises serve as a window through which to view these relations, and ‘social capital’ is used as an analytic for making sense of the human relations at the core of disaster management operations. These elements help to expose and substantiate the often intangible relations that compose the culture that exists, and that is shaped by preparations for disasters. The study reveals how this social capital has been generated through personal interactions, which are shared among disaster managers across different organisations and across ‘levels’ within those organisations. Recognition of these ‘group resources’ has significant implications for disaster management in which conducive social relations have become paramount. The paper concludes that socio‐cultural relations, as well as a people‐centred approach to preparations, appear to be effective means of readying for, and ultimately responding to, disasters. 相似文献
A disaster referred to by the press as the ‘UK flooding crisis’ occurred between December 2015 and January 2016. This study employed three different levels of analysis to identify a multidimensional perspective adopted in the disaster reporting of the British Broadcasting Corporation (BBC). These levels revealed details about the social actors and their interactions. The set of news exposed diverse viewpoints on the crisis, from loss and damage to distinct affected subgroups to the various social engagement actions of aid and the multiplicity of technical response measures. The conclusions highlight considerable social amplitude in the BBC's coverage; however, owing to the reductionist approach of this media communicator, the field of action involving different social actors was not very clear in the content of the news, particularly with regard to cohesion, conflict/obstruction, and concernthe concept of crisis in its essence. In addition, the paper suggests new questions for future reports. 1 相似文献
Human emissions of greenhouse gases are already changing our climate. This paper provides an overview of the relation between climate change and weather extremes, and examines three specific cases where recent acute events have stimulated debate on the potential role of climate change: the European heatwave of 2003; the risk of inland flooding, such as recently in Central Europe and Great Britain; and the harsh Atlantic hurricane seasons of 2004 and 2005. Furthermore, it briefly assesses the relation between climate change and El Ni?o, and the potential of abrupt climate change. Several trends in weather extremes are sufficiently clear to inform risk reduction efforts. In many instances, however, the potential increases in extreme events due to climate change come on top of alarming rises in vulnerability. Hence, the additional risks due to climate change should not be analysed or treated in isolation, but instead integrated into broader efforts to reduce the risk of natural disasters. 相似文献