The economies and livelihoods of many coastal megacities are at serious risk from flooding, despite investments in flood defenses. For instance, in Ho Chi Minh City, the construction of a large‐scale ring‐dike has mitigated negative effects from storm surges, yet damage is still frequently caused by high‐intensity rainfalls leading to nuisance flooding, which is responsible for the highest proportion of flood losses in the city today. Because sustainable flood risk management requires detailed spatial information, we analyze the local risk and its components based on a chain of novel models previously calibrated and validated for Ho Chi Minh City. Furthermore, we assess the effectiveness of two decentralized adaptation options, namely private precautionary measures and rainwater retention, for mitigating pluvial flooding. Our integrated risk assessment reveals that the approaches are complementary, which is a major advantage for their implementation. Implementation of both approaches has the potential to reduce the expected annual damage and the number of annually affected households by 16% and 56%, respectively. This is also reflected in a significant reduction of annual losses per household, which we propose as an additional, people‐centered indicator of flood risk. Moreover, these measures are well‐suited to strengthen citizen participation in risk reduction beyond top‐down protection schemes. Complementing the ring‐dike with decentralized adaptation options can therefore be seen as an effective and generic strategy to alleviate the impacts of nuisance flooding in coastal megacities, such as Ho Chi Minh City, and should be incentivized by decision‐makers. Aside from hydrological and metocean site conditions, both the methodology and findings of this study are transferrable to any coastal megacity facing similar challenges.

This research aimed at assessing climate trends and adaptation strategies to the impacts of climate change on rice producers in Nghe An province. For the first objective, multiple graphs, the Mann–Kendall test, and Sen’s Slope test were employed to analyze the secondary data of rainfall, temperature, and rice yield in Nghe An from 1995 to 2019. The results showed that the rice productivity of Nghe An increased over the 25-year period, annual rainfall decreased in the winter-spring season, and annual temperature increased in the summer-autumn season. For the second objective, primary data were collected by conducting household surveys of 396 households in Nghe An province. Sixty-two percent of farmers did not adopt any adaptive strategies, while other strategies included changing the planting schedule, growing stress-tolerant crops, improving irrigation practices, and utilizing fertilizer and other good practices. Multivariate probit regression (MVP) was employed to analyze the factors affecting the adaptation strategies of households in the study area. The results of MVP showed that age, education, gender, household size, farm size, cooperative, farmer organization, extension services, access to credit, access to irrigation, rainfall, and living in Quynh Luu or Dien Chau significantly affected the farmers’ choice. The results implied that farmers can obtain advanced technology, social learning, and community practices by participating in farmer organizations and cooperatives. In specified area, local authorities should invest in improving irrigation systems, practicing land consolidation, practicing special farming techniques, and providing timely weather forecasts for enhancing farmers’ resilience.

Sustainable forest management is facing threats such as deforestation, forest degradation, and biodiversity loss due to socio-economic conditions, a weak governance capacity, and lack of public participation. In Xuan Nha Nature Reserve, about 50% of the total population are living below the poverty level and their livelihoods are depending on forest. The community’s activities have been creating pressures on the forest by reducing the forest area, increasing forest land degradation, and through illegal logging. The objectives of the study were to (i) identify sustainable livelihood options; (ii) the most suitable livelihood practices with the purpose of reducing poverty for local communities and their dependency on forest resources; and (iii) recommend suitable policies to reduce the conflict between socio-economic development and forest management. In order to achieve these objectives, we used the LIFE (livelihood, income, forest condition, and equity); the Sustainable Livelihood Framework; and the Advocacy Coalition Framework. The results showed that fruit orchards and beekeeping were two suitable livelihood options for the buffer areas since there were more convenient assets such as roads, markets, and human knowledge, while fruit orchards and local pig farming were suggested for the ERA (ecological restoration area) and SPA (strictly protected area) to solve the problem of land degradation and maintain the traditional habits of the local community. Regarding policy changes, support for livelihood practices and improvement of the community’s and authorities’ awareness on forest protection was necessary for all the sub-areas for reducing poverty and the pressures on forest resources of the community.

Land resources potential assessment is a valuable method for orienting land use planning in the world as well as in Vietnam.The objectives of the study are (1) to assess land suitability and (2) to orient the effective use of agricultural land in the study area. Results indicated that Ham Thuan Bac has 107 land mapping units (LMU), in which includes 11 land-use types (LUTs) such as rice, corn, cassava and sweet potato, sugarcane, grass for livestock, vegetables, green dragon fruit, rubber, coffee, and other fruit trees. Agricultural land with high suitability (S1) and moderately suitable (S2) for mostly LUTs is small, however, marginally suitable (S3) and not suitable land (N) are quite large. More than 50% of the LUTs for growing rice, rubber, coffee, other fruit are not suitable; the remaining LUTs have unsuitable land ranging from 10.76% to 25.16% of agricultural land in the district. Based on land suitability classification, we propose to keep 8550 ha with S1, S2, and a part of S3 area to be irrigated for cultivating rice; 9071.7ha of dragon fruit land including 694.67 ha of S1 and 8377.03 ha of S2 land; and only cultivate annual crops, fruit trees and grazing grass on the land with suitble levels from S1 to S3 of the current status.The remainingareas ofS3 and N for riceand areas of S2 and S3for green dragon fruit under S2, S3with active and semi-active irrigation regimeswill be converted to annual crops and fruit trees and grass for livestock.

Land use/land cover (LULC) and climate changes are two main factors directly affecting hydrologic conditions. However, very few studies in Vietnam have investigated changes in hydrological process under the impact of climate and land use changes on a basin scale. The objective of this study is to assess the individual and combined impacts of land use and climate changes on hydrological processes for the Nam Rom river basin, Northwestern Viet Nam using Remote Sensing (RS) and Soil and Water Assessment Tools (SWAT) model. SWAT model was used for hydrological process simulation. Results indicated that SWAT proved to be a powerful tool in simulating the impacts of land use and climate change on catchment hydrology. The change in historical land use between 1992 and 2015 strongly contributed to increasing hydrological processes (ET, percolation, ground water, and water yield), whereas, climate change led to significant decrease of all hydrological components. The combination of land use and climate changes significantly reduced surface runoff (-16.9%), ground water (-5.7%), water yield (-9.2%), and sediment load (-4.9%). Overall climatic changes had more significant effect on hydrological components than land use changes in the Nam Rom river basin during the 1992–2015. Under impacts of projected land use and climate change scenarios in 2030 on hydrological process of the upper Nam Rom river basin indicate that ET and surface flow are more sensitive to the changes in land use and climate in the future. In conclusion, the findings of this study will basic knowledge of the effects of climate and land-use changes on the hydrology for future development of integrated land use and water management practices in Nam Rom river basin.