General: The Mekong river is the great river in the Asia Oceania region, which is the 10th largest river in a world with 4,400km length and 975,000 km2 area of watershed. The Mekong river originates from the Tibetan Plateau and runs through China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. The climate of the region has large varieties from glaciated Tibetan Plateau to the hot and humid tropical region, and most of the region is generally governed by the Asia Monsoon climate which has maximum rainfall during summer and less rainfall during winter. The total annual rainfall is measured at Lao to be around 3,000mm. Due to the heavy rainfall amount, total discharge rate in annual average is 15,060 tons/second. The natural resources are rich in forest, lake, wetland, brackish water and Mangrove region, and sustain regional and local societies through agriculture, aquaculture, surface fishery, biodiversity, tourisms, and transportations. Since the beginning of its history, the Mekong river has long been concerned with the human life and the ecosystem in these countries. Productions from natural resources are exported outside, and sustain regional and local economies.

Human activities and climate change are primary causes associated with environmental changes in the Mekong river basin. For example, human activities due to agriculture expansion and many man-made dams could have affected the river discharge and the local ecosystem. Recently due to the increase of anthropogenic impacts and human activities such as man-made dams and deforest, disasters in this region such as floods, droughts, biodiversity changes, coastal erosion have been bigger risks of disaster and environment than a past, and these impacts to society and economy have been increasing year by year. The resultant societal impact may be manifested in various fields of water management, agriculture, flood, energy, health, ecosystem, environmental pollution and transportation. It is therefore very important to perform case studies that characterize such environmental changes and eventually help to develop the operational solution for the benefits of our society.

The utilizations of our Earth Observation data will bring big benefits to provide solutions to these risks and to reduce these impacts to society and economy, and will help establishment of managements of these risks are needed.

Pilot area (Mekong River Delta): The Mekong Delta is the rich rice production area, but due to less river discharge and more use of river sand, sea waters have been more intruding into the delta area than before. The damage of salt soil to rice production is huge, so the environmental monitoring at the delta region by the Earth Observation is quite important. Coastal erosion is another issue in the delta. Due to the river sand use, sediment supply to the coast of the delta becomes less. The monitoring of the erosion of the delta by the Earth Observation is crucial.