Environmental/hydrological problems of the Mekong River Delta

The article shows how anthropogenic impacts on the hydrological regime in the upper part of the river basin together with climatic changes lead to an ecological catastrophe in the delta of the river. We have considered the Mekong River basin, which is located on the territory of six countries, where more than 30 hydroelectric power stations are already operating in the upper part of the basin, and another 10 are under construction. The number of hydroelectric power stations in the basin is planned to be increased to 170. The Mekong River Delta, completely located on the territory of Vietnam, is experiencing huge multifaceted problems. The delta has been growing towards the sea for many centuries, but in recent decades it has been receding, primarily due to a sharp decrease in the inflow of sediment in the delta, which is detained by numerous dams upstream. Uncontrolled until recently the extraction of sand and gravel mixtures from the riverbed also has an impact. On the other hand, the construction of hydraulic structures is not only a very important factor in the economic development of the basin countries, but also an important tool in combating the growing contrast of the climate, when floods are becoming more powerful, and the decline of the runoff in the dry period is becoming lower. Reduction of low-water runoff is exacerbated by the pumping out of groundwater for the needs of water supply. Reduction of the solid flow and low-water flow against the background of the growth of the world ocean level caused by climate change leads to a significant penetration of sea salt waters along the canal and channel systems into the delta. This has an extremely adverse effect on crop production and fish farming. At the same time, the Mekong Delta is the most important agricultural sector in Vietnam, accounting for more than 50% of total rice production and 60% of fish production. An article is devoted to the investigation of these problems and the identification of ways to solve them.