A fast increase of municipal solid waste (MSW) has become the most concerning environmental problem in Vietnam, especially in the Mekong Delta region, that is considered one of the most vulnerable deltas to climate change in the world. There are 12 provinces and one central city in MD that occupy about 12% of the whole area of the nation with 5% of MSW generated. However, there is no currently effective management system in place for treatment and management of MSW in the MD. Landfill is the sole treatment option for MSW right now. With a low-level plain, MD is facing the most serious environmental problem in the near future with an effect of climate change and sea level rising. The landfill should not be considered for long-term use in this area. Suitable treatment options for MSW should be applied together with other solutions for reuse, recycling and reduction of MSW as well as pollution prevention issue. An integrated MSW management approach in adaptation to climate change is considered necessary. / Sự tăng nhanh chất thải rắn đã trở thành vấn đề vấn đề môi trường được quan tâm nhất ở Việt Nam, đặc biệt là ở khu Đồng bằng Sông Cửu Long một trong những đồng bằng dễ bị tổn thương bởi sự biến đổi khí hậu nhất trên thế giới. Đồng bằng Sông Cửu Long có 12 tỉnh và một thành phố trực thuộc trung ương, chiếm 12% diện tích của cả nước với khoảng 5% lượng chất thải rắn phát sinh. Tuy nhiên, hiện nay chưa có một hệ thống quản lý hiệu quả cho chất thải rắn ở khu vực. Bãi rác là lựa chọn xử lý duy nhất ở thời điểm này. Với cao độ thấp, Đồng bằng Sông Cửu Long đang đối mặt với ảnh hưởng nghiêm trọng của các vấn đề môi trường trong tương lai gần bởi ảnh hưởng của sự biến đổi khí hậu và nước biển dâng. Về lâu dài bãi rác không nên sử dụng ở khu vực này. Các lựa chọn xử lý thích hợp cho chất thải rắn cần được áp dụng cùng với các giải pháp khác như tái sử dụng, tái chế và giảm thiểu chất thải rắn cũng như các giải pháp ngăn ngừa ô nhiễm. Cách tiếp cận quản lý tổng hợp chất thải rắn nhằm ứng phó sự biến đổi khí hậu cần được xem xét.

As environmental changes, including climate change, become more and more severe and affect every corner of the world, many people are forced to move from their homestead as the nearby environment that once was a safe place slowly becomes inhabitable. The Mekong Delta in southern Vietnam is one of the places in the world where environmental changes jeopardize rural livelihoods creating a trend of out-migration and urbanization. Through a Minor Field Study facilitated by the Swedish International Development Cooperation Agency, SIDA, this research was conducted in the Vietnamese Mekong Delta, specifically the An Biên District in Kiên Giang province. The empirical base did, from an ethnographically inspired qualitative method, collect primary data by using observation, semi-structured interviews, a group discussion, as well as expert interviews with key informants. The research aimed at generating insights and knowledge about local perceptions by investigating environmental changes’ connection to migration and integrating the frameworks Drivers of Migration and the Sustainable Rural Livelihoods approach. It found both that the perceptions of environmental changes impact on livelihoods and its relation to migration as adaptation was different depending on the type of agricultural activities. It also found that environmental changes partly had or did not at all have a relationship with migration as adaptation, but rather the financial and social conditions together with natural capital as the size of land.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第23964号 / 農博第2513号 / 新制||農||1093(附属図書館) / 学位論文||R4||N5399(農学部図書室) / 京都大学大学院農学研究科生物資源経済学専攻 / (主査)教授 梅津 千恵子, 教授 浅見 淳之, 准教授 三谷 羊平 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

The traditional explanation of the rapprochement between China and ASEAN has two elements: China is securing a peaceful environment to implement its strategy of ‘develop first’, and/or China is engaging in courtship for the ASEAN countries out of strategic considerations, i.e. increasing control of its periphery. In contrary to these traditional perspectives, this study argues that the intensifying of cooperation between China and ASEAN is much more an expression of the recognition of asymmetrical dependencies than of calculated foreign policy decisions. This perspective not only enriches the understanding of current regional political processes but also leads to different expectations regarding the stability and future direction of ASEAN – China relations. Two issue areas have been selected to illustrate the asymmetrical dependencies and the resulting political processes between ASEAN and China. It has been found that both the ASEAN countries and China have accommodated to asymmetrical interdependence by engaging in pay-offs in areas of relative power. China has not been able to use its relative power in the economic and military area to impose its will in other areas of ASEAN-China relations. The bargaining has taken place within the existing ASEAN institutions. In their concrete rules and conventions lies considerable power. This explains the intensive bargaining regarding the importance of competing international organizations, not only in the Mekong River Basin, but also in broader regional politics. The ASEAN countries are in a favorable position, being in the center of these institutions, but China as a latecomer to many of the regional institutions is trying to renegotiate them. Further research is therefore indicated to better understand how the ASEAN countries and China are going to trade off potential gains from international cooperation and the loss of sovereign policy making power.

Nongovernmental organisations (NGOs) have come to play a major role in contemporary governance systems, and particularly in the fields of water and the environment. Adopting a new institutional theoretical perspective, this thesis examines how rules and norms affect the advocacy strategies of coalitions of NGOs in Vietnam and Cambodia, utilising a comparative case study analysis of the Xayaburi hydropower dam planned on the Mekong River in Laos. The comparison was conducted between the Rivers Coalition in Cambodia and the Vietnam Rivers Network during the planning period for the dams in 2011-2013.The main findings of the study is that rules, norms, actors, biophysical and material conditions interact with each other in creating influence over advocacy strategies. Different patterns of interactions were identified; these are 1) complementary interactions between formal rules, informal rules and norms 2) competing interactions between formal rules, informal rules and norms. Actors play important roles in both of these forms of interactions. Through identification of the barriers and opportunities NGO actors face within the Mekong region, the thesis concludes with two recommendations: 1) modifications to the formal rules which could facilitate further integration of NGOs and civil society actors into decision-making processes of transboundary water governance and 2) use of analytical framework by NGO and civil society actors in identifying windows of opportunities for advocacy strategies.

As Information and Communication Technology (ICT) and social enterprises become drivers of economic growth, the nexus provides opportunities for new models of business to bring benefits to communities in developing countries. Recognising the complex dynamics and range of actors in this diverse and emerging sector, this study chooses to document the external influences, use and impact of ICT on social enterprises. The problem investigated is the potential gap between the rhetoric of the 'promise of e-business' versus the dynamics of enactment and impacts of ICT in practice in the social enterprise sector. The methodology consists of a mixed-method data collection strategy to triangulate data sources from a diverse cross-section of organisations in the social enterprise sector in Cambodia. These include a cross-sectional survey, interviews, observations, document analysis and review of artefacts. It is unclear whether the Cambodian social enterprise sector represents a unique case or is representative of other countries. Regardless, the rich dynamics of the sector and the current lack of understanding of ICT use by this sector in developing countries per se warrant such a study. It fills a significant gap in the field of ICT and development by providing an in-depth overview of the social enterprise sector in one developing country, which may also be applicable in other developing country contexts. The research maps the e-business status of Cambodian social enterprises along a continuum from precursor activity to fully integrated e-services. It finds that Cambodian social enterprises believe ICT adds value to their operation; however access to affordable and reliable local ICT resources is an important factor determining long-term uptake. It also shows that external support is seen as vital to the success of ICT uptake by social enterprises in Cambodia. Donors have the most significant influence on social enterprises' framing of ICT, whilst NGOs, associations and the private sector are also important institutional players in shaping understanding and uptake of ICT. The main contribution of the research is to identify the real development impact of ICT use by social enterprises by measuring the role of ICTs in achieving their goals. Its major finding is that social and business missions are inextricably linked within these organisations, so to measure one in isolation of the other denies the new paradigm that social enterprises present. The most active sub-sector explored that best reflects this unique value proposition is the emerging social outsourcing potential of the IT services sub-sector. The handicraft and processing sub-sectors have yet to fully engage and use ICT to their maximum benefit. The outlook for these sub-sectors is likely to require further support to best harness the potential that ICT can bring developing countries.

More than a decade after the World Bank was forced out of the dam-building industry due to the social and environmental consequences of the projects they helped to finance, World Bank support for the development of the Nam Theun 2 (NT2) Hydroelectric Project, located atop the bio-diverse Nakai Plateau in central Laos, signals the re-emergence of the Bank’s involvement in large-scale dam construction initiatives. The NT2 project is the Bank’s response to its international critics. The project is a ‘test case’ for a new model of hydropower development that seeks to counteract any negative consequences to the surrounding environment and populations through the enactment of a new set of environmental and social safeguards that the Bank had spent over a decade developing. As the optimal consequence, if NT2 achieves the goal of safeguarding the bio-diverse environment of the Nakai region through the creation and implementation of long-term ‘socially and environmentally sustainable’ livelihood activities capable of raising the living standards and income levels of Nakai villagers beyond the national poverty line, then the NT2 model of development will be validated and its use in other World Bank supported hydroelectric initiatives all but assured. The alternative result is that the new safeguard mechanisms fail to achieve these goals, significantly contributing to the destabilization of one of the of the most environmentally and culturally unique regions in the world. This thesis analyzes the effectiveness of NT2 social and environmental safeguards in order to determine to what extent this new model of development is achieving the objectives it set prior to construction. Using a range of data, it analyzes outcomes produced from the core safeguards program of the project: the resettlement livelihoods’ programmes. Analysis of villagers’ livelihoods after resettlement clearly indicates that the NT2 model was never able to overcome challenges posed by reduced access to forest and agricultural lands for re-establishing villagers’ core land-based livelihood activities. As a result, many villagers have abandoned the livelihoods programmes at resettlement villages across the Plateau. In the short term, these villagers have, nevertheless, significantly increased their incomes through intensified commercial fishing and export-oriented rare timber and endangered wildlife extraction activities. The problem for NT2 developers such as the World Bank is that this form of economic activity is neither socially nor environmentally sustainable, placing the regional environment, local populations and the NT2 project in jeopardy. / Graduate

Le riz est la principale denrée de plus de la moitié de la population mondiale et joue un rôle particulièrement important dans l'économie mondiale, la sécurité alimentaire, la consommation d'eau, et le changement climatique. L'objectif de cette thèse consistait à développer des méthodes pour le suivi du riz basées sur des données Sentinel-1 ainsi qu'a utiliser les produits de cartographie obtenus dans diverses applications portant sur la sécurité alimentaire et l'environnement mondial. Plus spécifiquement, l'étude a pour but de fournir des outils pour observer la culture du riz, en produisant la cartographie des surfaces cultivées, celle des stades phénologiques de la plante comprenant le début de la saison, celle des deux principales catégories de variétés de riz à cycle court et cycle long, la hauteur de la plante, et la carte annuelle du nombre de récoltes de riz par an. Ces informations sont nécessaires à l'estimation de la production du riz, et à la gestion des cultures à l'échelle régionale. Nous étudions aussi l'intégration des produits ainsi développés dans un modèle de processus destinés à estimer le rendement du riz, et un modèle permettant la dérivation de l'émission du méthane et le volume d'eau nécessaire à la culture. La région test est l'une des régions rizicoles majeures à l'échelle mondiale, qui est le Delta du Mékong, au Vietnam. Cette région est caractérisée par une grande diversité de pratiques agricoles, du nombre de cultures du riz par an, et dans les calendriers des récoltes. La première phase du travail est la compréhension de la variation temporelle des valeurs de rétrodiffusion radar de Sentinel-1, en polarisation VH et VV. Pour cela, des données de terrain ont été collectées sur 60 champs, sur 5 saisons de riz pendant 2 ans. Les variations temporelles des mesures radar ont été interprétées en fonction de la croissance des plantes le long des stades phénologiques. Les mêmes courbes caractéristiques observées lors des 5 saisons ont suggéré l'utilisation d'une courbe 'type' dans le développement des méthodes pour fournir les produits requis. Les résultats obtenus sur le Delta du Mékong ont été validés à l'aide des données terrain de référence, et sont très satisfaisants : 98% de précision pour la carte riz/non riz, une RMSE de 4 jours pour la date de semis, une RMSE de 0.78 cm pour la hauteur de plante, 91,7% de précision pour la distinction entre deux types de riz (cycle court et cycle long), et 98% de précision sur l'estimation du stade phénologique. Enfin, nous avons évalué l'utilisation de ces produits issus de données Sentinel-1 dans le modèle ORYZA2000 destiné à estimer le rendement du riz, et dans le modèle DNDC destiné à estimer le volume d'eau nécessaire à la culture, ainsi que l'émission de méthane par les rizières. Les résultats, préliminaires, montrent le bon potentiel de l'approche pour fournir le rendement, le bilan d'eau, et les taux d'émission de méthane sur les champs de riz considérés. Cette approche permettrait de faire des analyses de sensibilité, par exemple pour optimiser la gestion d'irrigation afin de réduire la consommation d'eau et l'émission de méthane, tout en préservant le rendement du riz. Ces travaux, qui démontrent le potentiel des données Sentinel-1 pour le suivi du riz à large échelle, seront à compléter afin de réaliser des applications effectives opérationnelles. Il s'agira de renforcer les méthodes et de les tester sur différents systèmes rizicoles, et de poursuive l'étude sur l'intégration de ces produits de télédétection dans les modèles permettant d'évaluer la productivité, les besoins en eau et les émissions des gaz à effet de serre des rizières. / Rice is the primary staple food of more than half of world’s population and plays an especially important role in global economy, food security, water use and climate change. The objective of this thesis was to develop methods for rice monitoring based on Sentinel-1 data and to effectively use the mapping products in various applications concerning food security and global environment. Specifically, the study aims at providing tools for observation of the rice cultivation systems, by generating products such as map of rice planted area, map of rice start-of-season and phenological stages, and map of rice crop intensity, together with rice crop parameters such as category of rice varieties (long or short cycle), and plant height. The information to be provided is necessary for the estimation of crop production, and for the management of rice ecosystems at the regional scale. We also investigated on how the products derived from EO Sentinel-1 data can be integrated in process-based models for rice production estimation and methane emission estimation. The test region is one of the world’s major rice regions: the Mekong River Delta, in Vietnam. This region presents a diversity in rice cultivation practices, in cropping density, from single to triple crop a year, and in crop calendar. The first step was to understand the temporal variation of the backscatter Sentinel-1 backscatter of rice fields, at VH and VV polarizations. For this purpose, in-situ data have been collected on 60 fields during 2 years, for the 5 rice seasons. It was found that backscatter time series of rice fields show very specific temporal behavior, with respect to other land use land cover types. The temporal and polarization variations of the rice backscatter have been interpreted with respect to physical interaction mechanisms to relate the backscatter dynamics to the key phenological stages, when the plants change its morphology and biomass. Because the same trend of temporal curves was observed over 5 rice seasons, it was possible to derive a mean curve to be used in the methodology developed for detecting rice phenology, and deriving information such as the date of sowing, the rice varieties of long and short duration cycle, or plant height, at each SAR acquisition date. The methods have been developed and applied to the Mekong delta. Products validation provides a good agreement with the reference data sets: 98% in rice/non-rice accuracy, the sowing dates RMSE of about 4 days, plant height RMSE of 7.8 cm, the long/short variety map has 91.7% accuracy and for phenology, only one season has been processed with good detection rate of 59/60. Finally, the use of the rice monitoring products as inputs in two process-based models was assessed. The models are ORYZA2000 for rice production estimation and DNDC for methane emission and water demand estimation. Sentinel-1 data retrieved information (sowing date, phenology, long/short variety, plant height) were used as model inputs, giving good agreement with the results making use of ground survey only. Based on the two process models with inputs from Sentinel-1 data, it was possible to have an integrated result on rice yield, water use, and methane emissions. The preliminary results show a good potential for the optimization of water management in rice fields in order to reduce water use and GHG emission, without reducing the yield. To achieve the objective which is the effective use of Sentinel-1 data for rice monitoring for food security and global environment, more works need to be done concerning the consolidation of the rice monitoring method development and the integration of Sentinel-1 derived information in models aiming at estimating and predicting rice production, methane emission and water use

On retrouve des contaminations d’aquifèr à l’arsenic dans touts les deltaï de l'Asie du Sud-Est, y compris dans le delta du Mékong, ce qui affecte la santé de millions de personnes. L’arsenic est très sensible aux fluctuations des conditions redox qui sont générés par les cycles alternés humides/secs pendant la saison de mousson. Une étude sur les caractéristiques géophysiques et chimiques du sol et des eaux souterraines dans le district de An Phu, dans le haut du delta du Mékong au Vietnam, suggère une forté contamination à l’As dans cette région. Les données chimiques et géophysiques indiquent une forte corrélation entre concentrations dans les eaux souterraines anoxiques et conductivité des sols. La liberation de l’arsenic est associée à la dissolution réductrice induih par des microorganisms des colloïdes et (oxyhydr)oxydes de fer dans des conditions d'oxydo-réduction oscillantes. La présence de bactéries sulforéductrices a le potentiel de stabiliser l’arsenic dans la phase solide et de l’atténuer dans la phase aqueuse par adsorption / désorption de l’arsenic sur les (oxyhydr)oxydes, et / ou sulfures de fer via la formation de complexes thiols. En raison de la teneur en pyrite élevée dans les sédiments, l'oxydation de la pyrite peut abaisser le pH et conduire à l'inhibition de la réduction microbienne du sulfate et aime empêcher la séquestration de l’arsenic dissous. Bien que le cycle biogéochimique de l’arsenic dans un système dynamique d’oxydoréduction soit une problématique complexe, il a été possible de renforcer notre compréhension de ce système / Aquifer arsenic (As) contamination is occuring throughout deltaic areas of Southeast Asia, including the Mekong Delta, and affects the health of millions of people. As is highly sensitive to fluctuations of redox conditions which are generated by the alternating wet-dry cycles during the monsoonal seasons. A survey of geophysical and chemical characteristics of soil and groundwater in the An Phu district, located in the vicinity of the Mekong Delta in Vietnam, shows the occurrence high As aqueous concentration in this region. Chemical and geophysical data indicate a strong positive correlation between As concentrations in the anoxic groundwater and conductivity of soils. In addition, mechanisms of As release are shown to be associated with colloidal and iron (oxyhydr)oxides which undergo microbial mediated reductive dissolution under redox oscilatting conditions. The presence of sulfate microbial reduction potentially stabilizes As in the solid phase and diminish As in the aqueous phase through the adsorption/desorption of As onto iron (oxyhydr)oxides and/ or sulfides with formation of thiols complexes in solid phase. Because of the high pyrite content in sediment, pyrite oxidation may drop in pH values, leads to inhibition of sulfate reducing bacteria and reduces sequestration of dissolved As. Although the biogeochemical cycling of redox sensitive species such as As in dynamic systems is challenging, it has been possible to strengthen our collective understanding of such system.

Pesticide use in rice farming is a common practice in the Mekong Delta and poses ecological risks to aquatic organisms, the environment, and human health. This study focused on the ecological risk assessment of pesticide use in rice farming using the PRIMET model as a decision support tool to evaluate the risks of pesticide exposure, ecotoxicity, and risk characterization, as well as employing the species sensitivity distribution (SSD) assessment model to calculate the potentially affected fraction (PAF) of species based on the computed predicted environmental concentrations (PECs) from PRIMET. The study involved collating and analyzing data on pesticide inventories and the application of 138 farmers, which formed the basis for pesticide use, farming practices,environmental variables, and ecological indicators from two provinces in the Mekong Delta: Dong Thap and Hau Giang. This study showed that pesticide use was high with a wide range of pesticide types. The ecotoxicity assessment indicated that some pesticides pose a potential acute and chronic risk to non-target organisms. The active ingredient identified as posing acute toxicity risk with an ETR >100 is the insecticide indoxacarb, which belongs to the chemical class of oxadiazine of which Arthropods were seen to be highly sensitive to when exposed making them more at risk even at very low concentrations. In contrast, fish generally exhibit moderate tolerance and are sensitive to certain chemicals. The risk characterization revealed that the ecological risks of pesticide use were higher in Dong Thap than in Hau Giang due to differences in ecological conditions, pesticide practices, and farming systems. Overall, this study highlights the need for improved pesticide management practices in rice farming in the Mekong Delta region to reduce ecological risks and protect the environment and human health. The practical and theoretical implications of this study are discussed.