Assessment and mitigation of tangible flood damages driven by climate change in a tropical city: Hat Yai Municipality, southern Thailand.

Climate change-induced floods in tropical urban areas have presented a serious global challenge because of failed conventional stormwater management practices. This research aims to develop a comprehensive methodological framework for flood damage estimation and mitigation, particularly in a tropical urban city. In this study, interdisciplinary fields were integrated through statistical downscaling, hydrologic-hydraulic modeling, and the development of flood damage curves. Relationships between tangible flood damage and flood-borne outbreak with flood depths were elucidated to predict future damage. Various flood mitigation strategies were evaluated. Herein, Hat Yai Municipality in Southern Thailand was selected as the study area. The flood simulation was conducted for 2010 and the highest flood damage sensitivity was exhibited by non-commercial buildings due to significant commercial stock damage, which was followed by that observed for detached houses. There was a strong linear relationship between the number of patients infected with leptospirosis and flood depth (R2 = 0.85). For climate change studies, flood maps for storms with 20-, 50-, and 100-year return periods under the A2/RCP8.5 scenario were generated using hydrological-hydraulic 1D/2D model; these maps were applied with the developed flood damage curves for damage estimation. It was found that reducing flood damage by implementing agroforestry and expanding the main bypass channel provides comparable damage reductions of -25.5% and - 27.5%, respectively, under the worst-case scenario of a 100-year return period in 2040-2059. Therefore, to deal with uncertain climate change situations, the incorporation of structural and non-structural measures is recommended. Such a combination when coupled with an eight-hour flood awareness time can result in a damage reduction of -59.9%. A flood warning system was in high demand by residents in the area; however, damage reduction from this measure alone was not high (approximately -17.0%) when compared to that obtained with other measures; consequently, additional measures were needed.

Health Benefits of Urban Allotment Gardening: Improved Physical and Psychological Well-Being and Social Integration.

With an ever-increasing urban population, promoting public health and well-being in towns and cities is a major challenge. Previous research has suggested that participating in allotment gardening delivers a wide range of health benefits. However, evidence from quantitative analyses is still scarce. Here, we quantify the effects, if any, of participating in allotment gardening on physical, psychological and social health. A questionnaire survey of 332 people was performed in Tokyo, Japan. We compared five self-reported health outcomes between allotment gardeners and non-gardener controls: perceived general health, subjective health complaints, body mass index (BMI), mental health and social cohesion. Accounting for socio-demographic and lifestyle variables, regression models revealed that allotment gardeners, compared to non-gardeners, reported better perceived general health, subjective health complaints, mental health and social cohesion. BMI did not differ between gardeners and non-gardeners. Neither frequency nor duration of gardening significantly influenced reported health outcomes. Our results highlight that regular gardening on allotment sites is associated with improved physical, psychological and social health. With the recent escalation in the prevalence of chronic diseases, and associated healthcare costs, this study has a major implication for policy, as it suggests that urban allotments have great potential for preventative healthcare.

Both Direct and Vicarious Experiences of Nature Affect Children's Willingness to Conserve Biodiversity.

Children are becoming less likely to have direct contact with nature. This ongoing loss of human interactions with nature, the extinction of experience, is viewed as one of the most fundamental obstacles to addressing global environmental challenges. However, the consequences for biodiversity conservation have been examined very little. Here, we conducted a questionnaire survey of elementary schoolchildren and investigated effects of the frequency of direct (participating in nature-based activities) and vicarious experiences of nature (reading books or watching TV programs about nature and talking about nature with parents or friends) on their affective attitudes (individuals' emotional feelings) toward and willingness to conserve biodiversity. A total of 397 children participated in the surveys in Tokyo. Children's affective attitudes and willingness to conserve biodiversity were positively associated with the frequency of both direct and vicarious experiences of nature. Path analysis showed that effects of direct and vicarious experiences on children's willingness to conserve biodiversity were mediated by their affective attitudes. This study demonstrates that children who frequently experience nature are likely to develop greater emotional affinity to and support for protecting biodiversity. We suggest that children should be encouraged to experience nature and be provided with various types of these experiences.

Application of the analytic hierarchy process to the analysis of wastewater nutrient recycling options: a case based on a group study of residents in the city of Zurich.

The recycling of anthropogenic nutrients derived from the wastewater management systems is often characterized by a complex and uncertain scenario, due not only to the nature of the process but also to the involvement of different stakeholder groups. Over the past 10 years in Switzerland, policies regarding the use of sewage sludge as fertilizer have gradually shifted to a ban on use in agriculture. As a result, alternative methods for the recycling of anthropogenic nutrients may play a relevant role in the near future. This paper uses the analytic hierarchy process (AHP) to examine more closely the nutrient-recycling dilemma by analysing the preferences of a group of German-speaking residents in the city of Zurich for various management scenarios. Nutrient recycling by the use of urine separation toilets and the BioCon treatment process are presented as possible management alternatives in addition to current practice. The study shows that AHP can incorporate the respondents' preferences and multiple objectives when evaluating alternatives with different attributes.

Model development for household waste prevention behaviour.

Understanding waste prevention behaviour (WPB) could enable local governments and decision makers to design more-effective policies for reducing the amount of waste that is generated. By merging well-known attitude-behaviour theories with elements from wider models from environmental psychology, an extensive cognitive framework that provides new and valuable insights is developed for understanding the involvement of individuals in waste prevention. The results confirm the usefulness of the theory of planned behaviour and of Schwartz's altruistic behaviour model as bases for modelling participation in waste prevention. A more elaborate integrated model of prevention was shown to be necessary for the complete analysis of attitudinal aspects associated with waste prevention. A postal survey of 158 respondents provided empirical support for eight of 12 hypotheses. The proposed structural equation indicates that personal norms and perceived behaviour control are the main predictors and that, unlike the case of recycling, subjective norms have a weak influence on WPB. It also suggests that, since social norms have not presented a direct influence, WPB is likely to be influenced by a concern for the environment and the community as well by perceptions of moral obligation and inconvenience. Results also proved that recycling and waste prevention represent different dimensions of waste management behaviour requiring particular approaches to increase individuals' engagement in future policies.

Characteristics of MSW and heat energy recovery between residential and commercial areas in Seoul.

This paper analyzes the amount and characteristics of municipal solid waste (MSW) according to the inhabitant density of population and the business concentration in 25 districts in Seoul. Further, the heat energy recovery and avoided CO(2) emissions of four incineration plants located in residential and commercial areas in Seoul are examined. The amount of residential waste per capita tended to increase as the density of inhabitants decreased. The amount of commercial waste per capita tended to increase as the business concentration increased. The examination of the heat energy recovery characteristics indicated that the four incineration plants produced heat energy that depended on residential or commercial areas based on population and business. The most important result regarding avoided CO(2) emissions was that commercial areas with many office-type businesses had the most effective CO(2) emission savings by combusting 1 kg of waste. Assuming the full-scale operation of the four incineration plants, the amount of saved CO(2) emissions per year was 444 Gg CO(2) and 57,006 households in Seoul can be provided with heat energy equivalent to 542,711 Nm(3) of LNG.

Factors affecting waste generation: a study in a waste management program in Dhaka City, Bangladesh.

Information on waste generation, socioeconomic characteristics, and willingness of the households to separate waste was obtained from interviews with 402 respondents in Dhaka city. Ordinary least square regression was used to determine the dominant factors that might influence the waste generation of the households. The results showed that the waste generation of the households in Dhaka city was significantly affected by household size, income, concern about the environment, and willingness to separate the waste. These factors are necessary to effectively improve waste management, growth and performance, as well as to reduce the environmental degradation of the household waste.

A survey of recycling behaviour in households in Dhaka, Bangladesh.

This paper examines the factors that might influence recycling behaviour of the households in Dhaka city, Bangladesh. Information on recycling activity, socio-economic characteristics, and attitudes of the households towards recycling were obtained from interviews with 456 households in Dhaka. Logistic regression analysis was used to determine the dominant factors that might influence the recycling behaviour of the households. The results showed that environmental consciousness, the availability of storage space, and age (25-35 years) are significant positive predictors of recycling behaviour (at the 1% level). Another variable Income 2 (TK3,000-15,000) is also positively correlated with recycling (at the 5% level). Establishment of a recycling programme could be an effective strategy in implementing sustainable waste management in Bangladesh. For this strategy to succeed, however, active partnership between households and the waste management service department is required. The households' attitudes toward recycling should, therefore, be taken into consideration as should the results of this study, which are important indicators of households' positive attitudes toward sustainable waste management in Dhaka.

Drivers in current and future municipal solid waste management systems: cases in Yokohama and Boston.

Despite some progress, municipal solid waste (MSW) still poses pressure on cities and remains one of the major challenges in environmental management. There is no single solution to the problem since the drivers behind MSW systems may vary significantly from city to city. In this context, the development of a common strategy to attain a sustainable management has been increasingly difficult. This paper presents an issue-driven analytical framework to evaluate the past, present and future MSW management strategy for the cities of Yokohama and Boston considering four driver categories while evaluating if the relevance of these drivers has changed over time. These categories represent: (i) legal drivers (e.g. laws and regulations); (ii) technology development and institutional drivers (e.g. available technologies); (iii) regional and international drivers (e.g. solid waste flow as recyclable resources); and (iv) socio-economic drivers (e.g. population trends and public awareness). The analysis indicated that solid waste management capacity for both cases was under stress due to different reasons. In the case of Boston, the moratorium for disposal facilities played an important role while increasing population was a key driver for the city of Yokohama. The future management scenario suggests that various waste-to-energy alternatives and strong solid waste reduction policies will play a key role for Boston. In Yokohama, a shift on waste composition and generation triggered by a demographic change may open the path for new technologies while also considering the international demand of solid waste as a recyclable resource.

Willingness to pay for waste management improvement in Dhaka city, Bangladesh.

We employed the contingent valuation method to estimate the willingness to pay of the respondents to improve the waste collection system in Dhaka city, Bangladesh. Our objective was to estimate how WTP differs between respondents who received or did not receive door to door waste collection. The methodology consisted of asking people directly about their willingness to pay an additional waste collection service charge to cover the costs of a new waste management project. The mean value of WTP for areas that received waste collection service areas was higher than for residents of areas that did not but the difference was not statistically significant. The aggregate value of WTP of the respondents in Dhaka city was 7.6 million Taka (USD0.1 million).

Evaluating source separation of plastic waste using conjoint analysis.

Using conjoint analysis, we estimated the willingness to pay (WTP) of households for source separation of plastic waste and the improvement of related environmental impacts, the residents' loss of life expectancy (LLE), the landfill capacity, and the CO2 emissions. Unreliable respondents were identified and removed from the sample based on their answers to follow-up questions. It was found that the utility associated with reducing LLE and with the landfill capacity were both well expressed by logarithmic functions, but that residents were indifferent to the level of CO2 emissions even though they approved of CO2 reduction. In addition, residents derived utility from the act of separating plastic waste, irrespective of its environmental impacts; that is, they were willing to practice the separation of plastic waste at home in anticipation of its "invisible effects", such as the improvement of citizens' attitudes toward solid waste issues.

Report: citizen participation as a part of integrated solid waste management: Porto Alegre case.

This study presents the effects of citizen participation on integrated solid waste management. Porto Alegre was chosen as the area of study since its system is a good example for developing countries, based on the partnership between local government and the former scavengers' association that implements selective collection in the city. A life-cycle approach was used to estimate environmental loadings and economic costs based on solid waste generation, and a survey assessment tool was used to analyse social aspects. The results showed a decrease in environmental and economic impacts in the current situation, allowing Porto Alegre to have one of the most affordable integrated solid waste management systems in Brazil. The survey assessment pointed out that public campaign changed the perceptions and practices of most of Porto Alegre's citizens regarding solid waste management. On the other hand, it also pointed out that citizens need more education to increase their participation. Therefore, more research is needed to increase cooperation among all stakeholders, improve citizen participation, and consequently, further decrease the environmental impacts and economic costs.

Applying choice experiments to valuing the different types of environmental issues in Japan.

In this study, improvements of different types of environmental issues in Japan, (i) reduction of mortality risk due to exposure to suspended particulate matter (SPM), (ii) improvement of the water quality of an urban river, and (iii) protection of goshawks, were evaluated in monetary terms using choice experiments. It was found that the reduction of mortality risk and the improvement of the water quality were highly valued, while residents did not place high value on the protection of goshawks. However, scope sensitivity was not observed in the evaluation of each issue and the presence of moral satisfaction was revealed. Excluding the effect of lexicographic choices could partly solve the problem concerning scope sensitivity. The results suggested that non-scope sensitive values that were unrelated to or inconsistent with the level of environmental improvement could be estimated through choice experiments in this research.

Assessment of the environmental impact of management measures for the biodegradable fraction of municipal solid waste in São Paulo City.

There is increasing concern about landfilling of biodegradable wastes. Therefore, biological treatment processes such as composting and biogasification have been considered as alternative strategies for managing those wastes. In this work, life cycle assessment was employed to compare the environmental impacts of landfilling, composting, and biological treatment of municipal solid waste in São Paulo City, Brazil. Energy consumption, recovered resources, and emissions to air and water were quantified and analyzed in terms of their potential contribution to global warming, acidification, and nutrient enrichment impact. The results demonstrated that processes that require high levels of energy consumption, such as wastewater treatment, play an important role in the outcome of environmental impact potentials. It was found that the landfilling of all waste is generally the worst strategy from an environmental point of view. However, significant reductions in the resulting impacts can be accomplished through biogasification and composting of the biodegradable fraction. Regarding composting, the application of a biofilter for gas treatment reduced significantly the gaseous emissions.