Environmental knowledge and human experience: using a historical analysis of flooding in Ireland to challenge contemporary risk narratives and develop creative policy alternatives

Focusing on three of the largest coastal cities in the Republic of Ireland, this paper highlights the importance of a historical analysis of flood hazards in contextualising current events and potential future risks. Over the last decade, the cities of Dublin, Cork and Galway have experienced several major coastal, river and pluvial floods. In the aftermath of these floods, two distinct but related narratives have dominated public discourse and official responses. The first narrative presents recent floods as unprecedented and as possible evidence of climate change. The second constructs floods primarily as natural events and assumes that the optimal means of reducing flood losses is to prevent flood events. In this paper, I suggest that these narratives are not supported by a historical analysis of exposure and vulnerability to flood hazards in Irish cities. This paper draws primarily on newspaper archives to construct a record of past flooding that challenges these narratives in several ways and in doing so offers lessons for similar cities in other countries. I contend that these narratives are perpetuated by a narrow form of knowledge production (quantitative risk assessment) and a narrow range of data (numeric instrumental records). Incorporating a broader range of sources and data types into risk and vulnerability assessments may illuminate more creative strategies for reducing both contemporary and future flood losses.     

基于组合赋权法的宁波市城市生态系统质量评价

为评价宁波市城市生态系统质量状况,在建立城市生态系统质量指数(UEQI)评价模型的基础上,首先由不同等级指标值线性拟合得到的标准化函数进行原始数据的标准化,然后根据变异系数法与层次分析法相结合的组合赋权法确定指标权重,最后对宁波市9个评价区的城市生态系统质量进行评价对比。结果表明,2006年宁波市城市生态系统质量属于一般水平(UEQI=64),其中宁海县城市生态系统质量最高(UEQI=70),其次为余姚市(UEQI=69)、奉化市(UEQI=68)、主城区(UEQI=67)、北仑区(UEQI=65)、镇海区(UEQI=62)、慈溪市(UEQI=61)和象山市(UEQI=59),而鄞州区的城市生态系统质量最差(UEQI=53)。     

Emergy-based urban health evaluation and development pattern analysis

The objective of this study is to measure and evaluate the ecosystem health levels of 31 Chinese capital cities in 2004 through an emergy synthesis framework. A system of indicators was developed corresponding to the four factors of urban ecosystem health including efficiency, structure, impact and flux. Furthermore, combined with individual indices, an emergy-based urban ecosystem health index (EUEHI) was proposed to measure and evaluate the health levels among various typical cities in China, which offers an integrated evaluation tool in view of urban production, trade and consumption. The results showed that there are intrinsic differences among six clusters associated with driving mechanisms distinguishing the rankings of urban health levels. After lining the cities of similar health levels with cluster map, the spatial distribution of the urban health is found to be arch-shaped, increasing initially and then decreasing from coast to inner land. This kind of spatial hierarchy is per se compatible and consistent with the hierarchical theory of emergy synthesis. The results also revealed double restrictions of urban health between economy and environment. Moreover, the interaction analysis was used for mirroring the driving mechanism of urban ecosystem health. Three conclusions were arrived at. Firstly, environmental health is inversely related to the economic health in China, indicating that cities cannot achieve win–win between environment and economy in the current urban development mode. Secondly, based on economy-driven mode, four quadrants were divided in the city division map, wherein 43.33% of the concerned cities developed in high economy-restriction mode, which means low economic level is still an important limiting factor for the major cities of China. Finally, based on environment-driven mode, two sections were divided, of which weak environmental dominance mode expounds the special characteristics of urban environment with obvious fragility. 23.33% of the 30 cities were in the intermediate state, which means a few correspondingly unhealthy cities should develop concrete polices for the urban ecosystem restoration.     

Urban ecological security assessment and forecasting,based on a cellular automata model: A case study of Guangzhou,China

Forecasting changes in urban ecological security could be important for the maintenance or improvement of the urban ecological environment. However, there are few references in this field and no landmark research work has been reported, particularly quantitative research. A forecasting model for ecological security based on cellular automata (CA) was developed using preliminary spatial data from an ecological security assessment of Guangzhou conducted previously (1990–2005). The model was constrained using transformation rules based upon proposed planning for 2010–2020. A simulation accuracy of 72.09% was acquired. Using a one-bit assessment grid for 2005 as the starting state for the simulation, the model was used to forecast ecological security for 2020. This revealed that although the ecological security status would be improved relative to current trends, there would still be an overall decline in ecological security over the next 15 years. Even if new urban plans were implemented, landscape pattern analysis suggested a more scattered and homogenous distribution in the urban landscape of Guangzhou and significant variation in landscape characteristics among districts. This suggests that further measures must be adopted to reverse the current trends in Guangzhou's ecological security. The model highlights the need to make ecological protection an integral part of urban planning. This study demonstrates the potential of CA models for forecasting ecological security. Such models could make an important contribution to decision-making for regional governors and to the development of urban planning incorporating assessment and prediction of ecological security.     

Exploring the relationship between residential segregation and thermal inequity in 20 U.S. cities

A combination of the urban heat island effect and a rising temperature baseline resulting from global climate change inequitably impacts socially vulnerable populations residing in urban areas. This article examines racial/ethnic and socioeconomic inequities in the spatial distribution of exposure to urban heat in the context of climate justice and residential segregation in the U.S. An urban heat risk index (UHRI) is calculated from measures of land surface temperature, structural density, and vegetation abundance, acquired from summer 2010 remote sensing imagery. Twenty of the largest metropolitan statistical areas (MSAs) in the U.S. are selected and analysed using census tract-level socio-demographic data from the U.S. Census. Multilevel modelling is utilised to examine the statistical associations between urban heat, minority status, socioeconomic disadvantage, and MSA-level segregation of racial/ethnic minority groups. Variables representing socioeconomic status (i.e. household income, home ownership, and education level) are consistently and significantly associated with greater urban heat exposure. Minority status and measures of segregation have a significant but varied relationship with urban heat exposure, indicating that there are inconsistent associations with urban heat due to differing social geographies. Urban heat and social vulnerability present a varying landscape of thermal inequity in different metropolitan areas, associated in many cases with residential segregation.     

平原城市河流面源污染研究范围及方法的选择与效果比较

由于平原城市地貌起伏不大,较难划分城市河流的流域范围,使得与河道面源污染相关的研究范围的边界确定存在一定的困难。针对这一问题,本文对比了基于缓冲区和排水区的两种研究范围及方法。根据遥感影像,利用GIS提取研究区内土地利用信息并与河流水质进行回归分析,对比两种范围及方法所得出的结果,试图为城市河道污染物的研究及管理提供方法支持和理论依据。本文选取了天津滨海地区11条河流进行研究,结果表明：（1）选取城市排水区作为土地利用数据的方法能够与河流中污染物的发生,迁移的真实情况相符合,能够综合考虑不同的景观格局分布对于水质的影响,结合平原城市的特殊性反映土地利用与河流污染物之间的相关关系,在机理严谨性上优于使用缓冲区范围,在整体性上更为完整;（2）基于缓冲区的研究方法能够在一定程度上解释在地表径流作用下,河流近岸不同距离的土地利用类型对河流污染物的影响,如耕地对污染物的影响,河流近岸100 m缓冲区的联合显著性为0.848,300 m缓冲区的仅为0.165;（3）土地利用类型对河流中污染物类型的贡献和消减趋势基本一致,城市居民点与工矿用地是河流当中重金属污染物如铅、汞的主要输入源;耕地对重金属等污染物有一定的截留消减作用,但在面积较大时增加了河流的有机污染物如氨氮;林地、园地、草地和水体对于城市河流污染物有一定的净化作用。两种方法结合起来可以得出更为详尽、客观的研究结果。     

Valuing floodplain protection and avoidance in a coastal watershed

Flood‐related losses in the United States are increasing despite large‐scale mitigation efforts. To offset the rising cost of floods, the US Congress passed legislation in 2014 that will augment insurance premiums to make the National Flood Insurance Program more actuarially sound. Consequently, there is interest in lowering flood‐related costs to the homeowner, both in terms of premiums and damage. This study addresses the issue by integrating premium savings and damages avoided based on several mitigation scenarios. Specifically, it examines how much policyholders within a watershed near Houston, Texas, could have saved between 1999 and 2009 had their communities introduced specific avoidance‐based mitigation activities. The results indicate that homeowners and communities can offset premium rises and a majority of the damage suffered through marginal expansions of such initiatives. However, the costs associated with their implementation could counter some of these savings, and hence they need to be considered in future work.     

Can floor-area-ratio incentive promote low impact development in a highly urbanized area?—A case study in Changzhou City,China

As an environmental friendly measure for surface runoff reduction, low impact development (LID) has been applied successfully in urban areas. However, due to high price of land and additional expense for LID construction in highly urbanized areas, the developers of real estate would not like to proceed LID exploitation. Floor area ratio (FAR) refers to “the ratio of a building’s total floor area to the size of the piece of land upon which it is built.” Increasing FAR indicates that the developers can construct higher buildings and earn more money. By means of awarding FAR, the developers may be willing to practice LID construction. In this study, a new residential district is selected as a case study to analyze the tradeoff between the runoff reduction goal achieving by LID practices and the incentive of awarding FAR to promote LID construction. The System for Urban Stormwater Treatment and Analysis IntegratioN (SUSTAIN) model is applied to simulate the runoff reduction under various LID designs and then derive the Pareto-optimal solutions to achieve urban runoff reduction goals based on cost efficiency. The results indicates that the maximum surface runoff reduction is 20.5%. Under the extremity scenarios, the government has options to award FAR of 0.028, 0.038 and 0.047 and the net benefits developers gain are 0 CNY, one million CNYand two million CNY, respectively. The results provide a LID construction guideline related to awarding FAR, which supports incentive policy making for promoting LID practices in the highly urbanized areas.

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Flooding: what is the impact on pregnancy and child health?

Floods are the most common type of natural disaster in both developed and developing countries and have led to extensive morbidity and mortality throughout the world. Worldwide, over the past 30 years, flooding has claimed the lives of more than 200,000 people and affected more than 2.8 billion others. The impact of flooding on health varies among populations and depends primarily on vulnerability and the kind of event experienced. It severely disrupts livelihoods and has a significant impact on the health of pregnant women and children. In addition, it may exacerbate a range of negative psychological and physiological child and reproductive health outcomes. Awareness‐raising, education, and the issuing of warnings appear to be key initiatives to mitigate or prevent flood morbidity and mortality, especially among people living in low‐ and middle‐income countries. Agencies responding to emergencies also need to be more cognisant of the dangers, specifically those engaged in healthcare, nutrition, and water safety programmes.     

基于SVM的CO2驱油藏输油管道脆弱性评价研究

CO2驱油在全国范围内的广泛开展导致内外扰动对输油管道的威胁大大增加,为指导企业发现输油管道的薄弱点从而预防事故发生,提出CO2驱油藏输油管道脆弱性概念及研究思路。将脆弱性分为5个等级并确定各级脆弱性的取值范围。深入分析脆弱性要素,从致灾因子、承灾体和灾害响应3个方面建立脆弱性评价指标体系,并确定各等级脆弱性对应的指标范围。利用MATLAB R2013a的SVM回归方法,构建脆弱性评价模型并进行实例应用。结果表明:模型训练的输出与期望输出拟合较好,均方误差为9.98052×10-7;训练好的SVM模型具有较强的泛化能力和较高的准确性,其对检验样本脆弱性进行预测的最大相对误差为0.027。利用模型得到研究区域某输油管道的脆弱性值为0.381,其脆弱性程度为不太脆弱。