Densely populated coastal urban areas are often exposed to multiple hazards, in particular floods and storms. Flood defenses and other engineering measures contribute to the mitigation of flood hazards, but a holistic approach to flood risk management should consider other interventions from the human side, including warning information, adaptive behavior, people/property evacuation, and the multilateral relief in local communities. There are few simulation approaches to consider these factors, and these typically focus on collective human actions. This paper presents an agent-based model that simulates flood response preferences and actions taken within individual households to reduce flood losses. The model implements a human response framework in which agents assess different flood scenarios according to warning information and decide whether and how much they invest in response measures to reduce potential inundation damages. A case study has been carried out in the Ng Tung River basin, an urbanized watershed in northern Hong Kong. Adopting a digital elevation model (DEM) as the modeling environment and a building map of household locations in the case area, the model considers the characteristics of households and the flood response behavior of their occupants. We found that property value, warning information, and storm conditions all influence household losses, with downstream and high density areas being particularly vulnerable. Results further indicate (i) that a flood warning system, which provides timely, accurate, and broad coverage rainstorm warning, can reduce flood losses by 30–40%; and (ii) to reduce losses, it is more effective and cheaper to invest early in response measures than late actions. This dynamic agent-based modeling approach is an innovative attempt to quantify and model the role of human responses in flood loss assessments. The model is demonstrated being useful for analyzing household scale flood losses and responses and it has the potential to contribute to flood emergency planning resource allocation in pluvial flood incidents.

This article proposes a systematic analysis of water management and allocation on the scale of a river basin, considering climate impacts and stakeholder networks in the Dongjiang River basin in South China. Specific approaches are integrated to explore various subtopics. Findings indicate a slight increase of precipitation in the basin and strong fluctuations in this century due to climate extremes, which may lead to seasonal or quality-related water shortages. It is highlighted that alternative options for holistic water management are needed in the basin, and participatory water allocation mechanisms and establishment of a basin-wide management framework could be helpful.

Sustainable flood risk management (SFRM) has become popular since the 1980s. Many governmental and non-governmental organisations have been keen on implementing the SFRM strategies by integrating social, ecological, and economic themes into their flood risk management (FRM) practices. However, the justifications for SFRM are still somewhat embryonic, and it is not yet clear whether this concept is influencing current policies in different countries. This paper reviews the past and current flood management experiences from flood defence to SFRM in four developed countries to highlight lessons for coastal megacities in development. The paper explores recent strategies such as “Making Space for Water”, Planning Policy Statement 25 (PPS25), and the National Planning Policy Framework (NPPF) in the UK and “Room for the River” in the Netherlands, which were implemented to mitigate flooding, integrate FRM with sustainability concepts, and deliver sound FRM practice for future generations. In this context, the United States has also established a National Flood Insurance Program (NFIP), and in a different approach, Japan has developed an advanced flood warning and evacuation contingency system to prepare for climatic extremes. These case studies give good lessons in achieving long-term SFRM to deliver sound flood management practices considering socio-economic and environmental concerns. Most developing coastal megacities especially in Asia are still heavily reliant on a traditional hard-engineering approach, which may not be enough to mitigate substantial risks due to human factors (e.g. large population, rapid socio-economic growth, subsidence from excessive groundwater extraction) and natural factors (e.g. climate change including sea-level rise and land subsidence). It is clear that different countries and cities have their interpretation of SFRM, but this paper explores how policymakers can adopt “mixed options” to move towards long-term thinking about sustainability with social, economic, and environmental considerations.

This study adopted an empirical analysis to explore social resilience to major natural disasters along the Tea-Horse Road (THR) in southwest China and to understand why and how the THR and its connected communities maintained and developed over a long period. A set of archive data, literature re-analysis, statistical data, monitoring data, and surveyed materials were collected and qualitatively and quantitatively analysed to support a holistic investigation of disaster impacts and social resilience. The results indicate that (a) natural disasters occurred frequently but were distributed over place and time and had various impacts, which left possibilities for maintaining social development with diverse and specific coping strategies; (b) strong central and local governance continually improved infrastructure and engineering technologies, and collaboration in social networks with local experience and disaster cultures were the major contributing factors that enhanced social resilience at various levels; (c) the THR area demonstrated various features of social resilience to natural disasters in terms of spatial-temporal scales, where the combination of multiple resilience measures enabled the resilience of the entire social system at various places over long time periods. Generally, larger social systems with diverse response capabilities were more resilient than small and individual entities over a long time scale. The study highlights that the THR region withstood frequent natural disasters but maintained a general development of social economy, transportation, and advanced technologies, and performed a positive transformation to a more resilient status. Overall, this paper describes the scale effects of multiple resilience measures along the THR and calls for specific studies on social resilience and transformation of diverse social entities over multiple spatial-temporal scales.

Several approaches have been used to assess potential human exposure to environmental stresses and achieve optimal results under various conditions, such as for example, for different scales, groups of people, or points in time. A thorough literature review in this paper identifies the research gap regarding modeling approaches for assessing human exposure to environment stressors, and it indicates that microsimulation tools are becoming increasingly important in human exposure assessments of urban environments, in which each person is simulated individually and continuously. The paper further describes an agent-based model (ABM) framework that can dynamically simulate human exposure levels, along with their daily activities, in urban areas that are characterized by environmental stresses such as air pollution and heat stress. Within the framework, decision-making processes can be included for each individual based on rule-based behavior in order to achieve goals under changing environmental conditions. The ideas described in this paper are implemented in a free and open source NetLogo platform. A basic modeling scenario of the ABM framework in Hamburg, Germany, demonstrates its utility in various urban environments and individual activity patterns, as well as its portability to other models, programs, and frameworks. The prototype model can potentially be extended to support environmental incidence management through exploring the daily routines of different groups of citizens, and comparing the effectiveness of different strategies. Further research is needed to fully develop an operational version of the model.

The Grassland Ecological Protection Award Policy was implemented to address severe grassland degradation in China. This policy utilizes grassland subsidies as an incentive to control the number of livestock and has become the largest payment for ecosystem services program. Although many studies have analyzed the performance of this policy, it remains controversial as to whether grassland subsidies are effective at reducing the number of livestock; moreover, there is still a lack of quantitative studies on the roles of household livelihood assets and livelihood strategies in reducing the number of livestock. On the basis of the sustainable livelihood framework, this paper constructed an analytical framework to research how grassland subsidies affect the number of livestock under the effects of different livelihood capitals and local socioecological contexts. After choosing the Pumqu River Basin of the Tibetan Plateau as the research area, this study classified sample households on the basis of grassland sizes and then examined the effects of grassland subsidies on the number of livestock of different groups of rural households by considering livelihood capital. The results showed that (1) for all the sample households, grassland subsidies caused herdsmen to raise more livestock, which was contrary to the expectation of the grassland protection policy. The invalidation of grassland subsidies was mainly caused by the poor design and implementation of the policy at the local level. (2) In addition, for rural households with different grassland sizes, the subsidies could be effective in reducing the number of livestock for households with small grassland sizes while increasing the number of livestock for households with large grassland sizes. This indicates that some supporting policies and measures for households with smaller grassland sizes should be provided to stimulate the reduction in the number of livestock, and for households with large grassland areas, grassland circulation should be encouraged to promote the large-scale production of livestock husbandry. The finding of this study can help governments to formulate policies tailored towards appropriate subsidies for addressing grassland degradation.