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Groundwater is vital and dependable source of water for drinking, agriculture and industries. The Central Godavari Delta of East Godavari district, Andhra Pradesh, is composed of alluvium wherein fresh and saline pockets exist together in close proximity. The present study is to identify freshwater pockets using geomorphological, land-use/land-cover, geophysical and geochemical analysis. Groundwater samples are analysed for electrical conductivity which revealed that about 35% of area is occupied by freshwater pockets in the north western and eastern parts. Vertical electrical sounding data inferred that resistivities less than 5 ohm-m is clay/sand with saline water; 5-10 ohm-m sandy clay and 10-75 ohm-m corresponds to freshwater zone. Freshwater pockets at depths greater than 8 m observed in northern part and shallower depths in southern parts. This integrated study proved successful in identification of fresh groundwater pockets in the delta region. [ABSTRACT FROM AUTHOR]

The dominant movement of people in the mega-deltas of Asia is from agriculture-dominated rural areas to urban settlements, driven by growing opportunities, but resulting in new human development challenges. In this context, the present study aims to investigate whether remittance income leads to enhanced multiple dimensions of well-being in sending areas in deltas, by focusing on two delta regions with significant out-migration rates, Bangladeshi Ganges Brahmaputra and the Vietnamese Mekong deltas. The paper develops a conceptual framework that draws on existing migration theories and the aspirations and capabilities theories. Data from large scale sample household surveys (2010 Bangladesh Household Income and Expenditure Survey and 2012 Vietnam Living Standards Survey) are analysed through multilevel regression modelling to examine well-being outcomes in sending areas and links to remittance income. The results show that the temporal extent of internal and international migration is positively associated with remittances in both delta regions. The results also suggest that in both delta regions remittances have a significant positive effect on household well-being in the source rural areas, including overall income, investments in health, food security and access to sanitation. The study concludes that landscapes of urban and rural deltas are increasingly economically integrated which suggests greater resilience even for environmentally-at-risk tropical deltas. [ABSTRACT FROM AUTHOR]

Historical land-cover changes in three delta regions in Southeast Asia are assessed by using selected Landsat images from 1990 to 2005. Potential inundation areas of the delta regions for different return periods are estimated by using digital elevation model data and extreme-value distribution of annual maximum river discharges. The results indicate significant changes of natural land cover within the potential inundation areas due to agricultural exploitation and industrialization. Implications for flood-mitigation policies are discussed. There is a clear need for sustainable land-use management strategies in all three areas. [ABSTRACT FROM AUTHOR]

Non-climate-related anthropogenic processes and frequently encountered natural hazards exacerbate the risk in coastal zones and megacities and amplify local vulnerability. Coastal risk is amplified by the combination of sea level rise (SLR) resulting from climate change, associated tidal evolution, and the local sinking of land resulting from anthropogenic and natural hazards. In this framework, the authors of this investigation have actively contributed to the joint European Space Agency (ESA) and the Chinese Ministry of Science and Technology (MOST) Dragon IV initiative through a project (ID. 32294) that was explicitly designed to address the issue of monitoring coastal and delta river regions through Earth Observation (EO) technologies. The project's primary goals were to provide a complete characterization of the changes in target scenes over time and provide estimates of future regional sea level changes to derive submerged coastal areas and wave fields. Suggestions are also provided for implementing coastal protection measures in order to adapt and mitigate the multifactor coastal vulnerability. In order to achieve these tasks, well-established remote sensing technologies based on the joint exploitation of multi-spectral information gathered at different spectral wavelengths, the exploitation of advanced Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques for the retrieval of ground deformations, the realization of geophysical analyses, and the use of satellite altimeters and tide gauge data have effectively been employed. The achieved results, which mainly focus on selected sensitive regions including the city of Shanghai, the Pearl River Delta in China, and the coastal city of Saint Petersburg in Europe, provide essential assets for planning present and future scientific activities devoted to monitoring such fragile environments. These analyses are crucial for assessing the factors that will amplify the vulnerability of low-elevation coastal zones. [ABSTRACT FROM AUTHOR]