Rendiconti Lincei. Scienze Fisiche e Naturali https://doi.org/10.1007/s12210-018-0695-6
Environmental changes near the Mekong Delta in Vietnam using remote sensing Bijeesh Kozhikkodan Veettil1,2 · Ngo Xuan Quang3,4 Received: 5 October 2017 / Accepted: 9 April 2018 © Accademia Nazionale dei Lincei 2018
Abstract This study is an attempt to use satellite imagery for the assessment of environmental changes near the Ba Lai River, Mekong Delta, in Vietnam. Landsat imagery was used to calculate water quality variables as well as land cover changes near Ba Lai River, both before and after the construction of an irrigation dam in 2002. A lot of changes in land use and land cover were observed in this area since the construction of the Ba Lai dam, particularly in the agricultural practice such as rotational plantation of rice and other crops. The present study stated that water quality has decreased and became polluted with organic materials between 1988 and 2006. Water quality variables such as chlorophyll (algae), nitrogen, and phosphorus were highly increased, whereas turbidity levels have slightly increased since the dam construction, possibly due to alluvial silty deposition. Keywords Ba Lai River · Ecosystem · Landsat · Mekong delta · Water quality variables
1 Introduction Coastal regions are a part of dynamic system which responds to geomorphological and oceanographical factors (Balica et al. 2012). It has been reported that many estuarine regions in the South East Asia are under the threat of sea lever rise and saline water intrusion into nearby freshwater systems under the current global warming scenarios (IPCC 2001, 2007). Mekong delta in Vietnam is an example as it is estimated that nearly 1 million people will be at the risk of being evacuated from this region by 2050 (MONRE 2009; IMHEN 2010). A 1 m sea-level increase is projected by 2100, enough to flood nearly 38% of this region (Tuan et al. 2012). Balica et al. (2009) identified four key components of vulnerability * Bijeesh Kozhikkodan Veettil
[email protected] 1
Department for Management of Science and Technology Development, Ton Duc Thang University, Ho Chi Minh City, Vietnam
2
Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam
3
Department of Environmental Management and Technology, Institute of Tropical Biology (ITB), Vietnam Academy of Science and Technology, Ho Chi Minh City, Vietnam
4
Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
to flooding—social, economic, environmental, and physical. While social components are related to the daily lives of population in the vulnerable region, economic components influence the income-related issues such as agriculture and fisheries. Environmental (e.g., ground water level, land use, urbanization rate, and pollution) and physical components (e.g., topography, rainfall, and turbidity) are most visible due to their immediate effects and many of them can be identified using remote sensing techniques and are considered in this research. Other than global warming, anthropogenic activities may also influence the vulnerability of human life towards environmental changes in estuarine regions. For example, there was an increase in shrimp farming in Ben Tre province in Vietnam recently which caused threats to coastal mangroves (Tuan et al. 2012). Pollution of water is another problem associated with heavily populated deltas due to particulate and organic waste discharge from urban areas and algal bloom in the summer. On the contrary, some manmade structures, such as dams and reservoirs, can be used for proper exploitation of natural resources without causing harm to the environment. In this context, proper assessment of environmental impacts in the estuarine region is important. One of the methods to prevent sea water intrusion into freshwater streams during tides is to construct dams after a proper environmental impact assessment. This would
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