Solutions to ensure water security against saline intrusion in Mekong Delta

Saline intrusion is assessed as one of the long-term challenges facing the Mekong Delta (MRD) and tends to be more severe in the future.
Saline intrusion is becoming more and more serious

According to the National Center for Socio-Economic Information and Forecasting (Ministry of Planning and Investment), the Mekong Delta is the largest agricultural production region of our country, playing an important role in the national economy, especially is in ensuring national food security. However, the Mekong Delta is a coastal lowland area, so every year, the sea water intrudes deeply into the mainland. Saline intrusion is a big challenge in the Mekong Delta. Photo: VGP This phenomenon appears cyclical and usually occurs sharply in the dry season months, from November to May every year. Saline intrusion is often affected by a number of factors such as flow from upstream to the Mekong Delta; flows in rivers, canals in interior fields; the tidal regime in the Mekong Delta; climate change, human impacts in water exploitation and use. In the past 6 years, the Mekong Delta has experienced two record saline intrusion waves, with intense and fierce intensity in 2015/2016 and 2019/2020, leading to a shortage of fresh water. wide, seriously affecting production and people’s daily life … In the dry season 2020/2021, saline intrusion in the Mekong Delta is higher than the average for many years, but not as serious as the dry season in 2019/2020, but the situation is also quite complicated. Up to the end of February 2021, in the Mekong Delta, there appeared 3 times of high saline intrusion, the salinity boundary 4g / l in Vam Co Dong river and Vam Co Tay river is 30-32km lower than the same period in 2020; the 4g / l salinity boundary in the estuaries of the Mekong River is 5-25km lower than that of the same period in 2020; The salinity boundary of 4g / l on Cai Lon river is 10-13km lower than that of the same period in 2020. Salty drought has damaged many areas of rice, fruit trees, aquaculture and vegetables, both agricultural production activities and daily life of the people are negatively affected. Saline intrusion combined with water shortage due to the effects of the saline drought season in 2019/2020 makes the total flow to be less than the average for many years and agricultural production is seriously affected. An estimated 40,000 ha of fruit trees (Tien Giang 19,000 ha, Ben Tre 15,000 ha, Vinh Long 1,800 ha, Soc Trang 3,400 ha) and about 5,000 ha of rice in Tra Vinh province have a shortage of irrigation water. With people’s lives, drought also makes many households seriously lack of water for daily use, even water supplied from clean water plants in urban areas in many provinces also shows signs of salinity. The main cause of saline intrusion in the Mekong Delta in 2020/2021 is attributed to the lack of rainfall, water resources in the upper Mekong River upstream during the 2020 flood season, and the 2020 flood peak at the upstream of the Mekong River on the Tien River. , the Hau river (An Giang province) is at a low level (below alert 1), leading to a shortage of flow in the dry season 2020-2021 from the upper Mekong river delta to the Mekong Delta by 10-20% compared to the average of many years. In addition, the total flow from the upper Mekong River (at Kratie station, Cambodia) to the Mekong Delta is in shortage compared to the average of many years about 5-15%. Solutions to ensure water security According to the National Center for Socio-Economic Forecasting and Information (NCIF), in the coming time, it is necessary to always be prepared with situational solutions to help people cope with urgent drought such as plan to mobilize mobile tank trucks to carry fresh water for households living in scattered, remote, coastal and island areas. Along with that, deploying drilling wells to supplement fresh water sources, extending pipes from concentrated water plants in the freshwater area to supply affected residential areas, installing additional public taps to supply households affected by saline intrusion use. Review, upgrade, expand and extend the pipeline with neighboring works with excess capacity to supply clean water to the people in the affected area. Regularly observe the water level of the reservoir, check the used capacity and the remaining capacity in the reservoir for treatment solutions to adjust irrigation water to suit production reality. Concentrate on investigating and searching underground water sources, especially deep aquifers to serve water supply for daily life in areas frequently subjected to saline water intrusion. Installation of salt water and brackish water filtration systems (RO equipment) in rural centralized domestic water supply schemes that are frequently affected by saline intrusion. To build freshwater reservoirs in dead-end canals and old diversion dams, and temporary dams to prevent salinity to keep fresh water sources for concentrated rural water supply stations. Investing in the construction of closed irrigation systems, implementing projects on dykes, embankments, key irrigation dams to prevent salinity, fresh storage for production and people’s livelihood. Saline intrusion negatively affects agriculture. The next solution is to regularly dredge the inland canals, clear and clear the flow for all canals, repair damaged works, carry out maintenance and repair of machines and equipment. operation, backup pumps to ensure proactive in regulating for irrigation and water pumping when saline drought, efficient operation of freshwater reservoirs. NCIF also believes that it is necessary to promote cooperation in the Mekong-Lan Thuong cooperation mechanism (MLC) on water exploitation and use. The decline in flow in the upper Mekong River leads to drought and saltwater intrusion in the Mekong Delta, so the water resource management in the Mekong Delta must be associated with the problems of water exploitation and use of 6 a country that shares the Mekong River. Accordingly, it is necessary to promote negotiations so that countries with large hydropower reservoirs, including in the main and tributaries, cooperate in the operation of power generation, water discharge downstream, ensuring flow maintenance. minimum level on the river. In addition, it is necessary to strengthen cooperation with countries experienced in responding to climate change, sea level rise, saltwater intrusion and drought such as the Netherlands, Israel, and Australia to enlist the help of countries and international organizations in coping with drought in particular and climate change in general It is necessary to widely propagate and guide people to implement measures to use water in an economical and efficient manner, especially in irrigation and daily life, to combat wasteful water sources. Encourage people to be proactive in case of water shortage with water storage solutions.