Mr. Do Duc Dung, Director of the Southern Institute of Water Resources Planning, said this when talking to reporters of Dan Viet Newspaper about the tense drought and saltwater intrusion situation in the Mekong Delta region.
In recent years, the Mekong Delta has always faced drought and saltwater intrusion. The 2023-2024 dry season is also taking place severely, with Kien Giang and Tien Giang provinces having to declare an emergency. A report from the Department of Irrigation (Ministry of Agriculture and Rural Development) also said that more than 73,000 people are lacking water for daily use. What is your assessment of the drought and saltwater intrusion situation this year?
- The impact of climate change (CC) has been affecting the whole world, the trend of extreme weather is increasingly appearing and occurring at a more dangerous level such as drought and salinity in 2015 - 2016, 2019 - 2020 and now 2023 - 2024, the frequency of occurrence is increasing. In the Mekong Delta, in addition to the impacts of extreme weather (El Nino), the impacts of upstream development will also have an impact on drought and salinity intrusion in this area.
The operation of upstream reservoirs has caused the salinity trend in the Mekong Delta to appear earlier at the beginning of the dry season, especially during this period when water intake is high for the Winter-Spring rice crop. In addition, El Nino will cause more water use and evaporation.
Mr. Do Duc Dung, Director of Southern Institute of Water Resources Planning.
The 2023-2024 drought and salinity have been forecasted/warned early since the middle of the 2023 flood season and the Government, the Ministry of Agriculture and Rural Development and localities have given very timely instructions and response solutions such as planting early winter-spring rice, strengthening solutions to increase water storage, in general, up to this point, ensuring production is basically completed, production losses are insignificant.
The drought and salinity in 2023 - 2024 is basically not as severe as in 2015 - 2016 and 2019 - 2020, which has confirmed that the forecasting/early warning work is quite good. However, for areas that completely use water stored from rain and coastal areas that cannot get fresh water due to high salinity intrusion such as: Go Cong Project, Long Phu - Tiep Nhat, Tran Van Thoi, U Minh Ha and U Minh Thuong, there has been quite serious subsidence due to the canal running out of water.
Drought and saline intrusion in the Mekong Delta are closely related to water resources in the basin, in which the water resources to the Mekong Delta are dominated by the flow to Kratie (on the Mekong River) and the amount of water stored in Tonle Sap Lake (Cambodia).
Specifically: The amount of water in Tonle Sap by the end of the 2023 rainy season is estimated at 35.14 billion m3, about 0.11 billion m3 lower than the average of many years. Up to now (April 11, 2024), the amount of water in Tonle Sap is only 1.53 billion m3 (about 0.54 billion m3 lower than the average of many years). The water level at Kratie station is currently about 6.96m, also 0.14m lower than the average of many years).
From that, it can be seen that the water source in the 2023-2024 dry season belongs to the group of years with little water, saltwater intrusion comes earlier and deeper than the average of many years.
According to the forecast of the National Center for Hydro-Meteorological Forecasting, the EL Nino phenomenon will last from December to March 2024, with temperatures 0.5-1.00C higher than the average, with little chance of unseasonal rain or insignificant rainfall, making drought and saltwater intrusion more serious.
The salinity situation in Tien Giang is serious, the canals are dry. Photo: Quang Sung
How is the current irrigation system in the Mekong Delta operated in regulating water, limiting drought and saltwater intrusion, sir?
- The Mekong Delta currently has 15 relatively complete irrigation systems (7 inter-provincial systems; 8 intra-provincial systems), with a service area of about 2.5 million (accounting for 64% of the Delta's area). Most of the irrigation systems have had their system operation procedures approved by the Ministry of Agriculture and Rural Development or localities to help ensure reasonable and targeted operation when building projects to meet production needs.
Regarding salinity control works along the main river, on the Hau River, there is a salinity control sluice to Rach Vop (Soc Trang) 50km from the sea, on the Tien River, salinity control is up to Cai Son sluice (Cai Lay, Tien Giang) 72km from the sea, on the Vam Co Tay River, salinity control is up to Tuyen Nhon 135km from the sea.
The salinity control sluices along the main river, when in operation, have controlled salinity intrusion into the fields. However, salinity intrusion beyond the control works will still affect production.
For closed irrigation projects that have been invested in coastal areas such as Go Cong, Nhat Tao - Tan Tru, Bao Dinh, Long Phu - Tiep Nhat, etc., the goal of controlling salinity is put first and has been well implemented. However, due to the lack of proactive fresh water supply, the amount of water stored in the fields is limited, so when salinity intrusion lasts for a long time, it still causes water shortages and droughts.
This year's drought also occurred in areas that do not have access to fresh water from the Hau River (especially Ca Mau), due to the lack of freshwater supply projects. Ca Mau can be considered a "depression" in irrigation in the Delta, which is also one of the current limitations of the irrigation system in the Mekong Delta.
This scene has become familiar to people in Go Cong Dong district (Tien Giang province) for nearly a month. Photo: Quang Sung
- It has been 12 years since the Prime Minister approved the Master Plan for Irrigation in the Mekong Delta for the period 2012-2020, with a vision to 2050 under the conditions of climate change and sea level rise (QH 1397) in 2012. Overall, it can be seen that irrigation systems in the Mekong Delta have gradually formed on a large scale in the direction of more effective control and regulation of all water sources, focusing on freshwater from the upper Mekong River and saltwater from the East Sea and the West Sea, increasingly serving socio-economic activities, especially agricultural production, aquaculture and domestic water supply.
Irrigation systems with the task of ensuring exploitation, control/regulation to create a water supply source that ensures quantity and quality for daily life with a population of 17.5 million people; supplying water for 26,450 hectares of industrial land (NGTK data in 2022); and supplying irrigation water for 3.94 million hectares of rice land for the whole year (Winter-Spring rice 1.53 million hectares, Summer-Autumn rice 1.63 million hectares and Autumn-Winter/Season rice 0.78 million hectares).
In addition, irrigation works also ensure water sources for nearly 400,000 hectares of fruit trees; more than 100,000 hectares of freshwater aquaculture and more than 676,000 hectares of brackish water aquaculture.
Specifically, there are 2 groups of projects to solve 2 key problems of the Mekong Delta region in recent times.
One is on flood control: After 12 years of implementation, the total number of completed works is 126/172 works/construction clusters, reaching 78.7% in terms of number of works, helping to basically stabilize production and daily life of people in flood-prone areas with a natural flood-prone area of about 2 million hectares.
The general assessment for this group is as follows: The construction works basically meet the schedule set for the period of 2020. Implementing the planning, many irrigation works have been invested to serve socio-economic development, meeting development needs.
A flood control dike system has been established that is relatively suitable to the flood characteristics of the region, ensuring good flood control at the beginning of the season for deep flooded areas and throughout the year for shallow flooded areas.
The flood drainage system has been formed, with relatively uniform and sufficient density, helping to increase the effectiveness of acid removal, alum washing and flood drainage.
The implementation of the electric pumping station program in the upper regions in provinces such as An Giang and Dong Thap was quite synchronous and rapid from 2015-2021, helping to increase the number of electric pumping stations and the area of irrigation by motor, enhancing the ability to proactively adapt to floods.
Flood-proof residential clusters have been formed, helping people live safely, stably and gradually develop sustainably. Specifically, 863 residential clusters and routes and 119 existing residential embankments have been completed, ensuring safety for about 191,000 households, with nearly 1 million people in flood-prone areas.
Second, regarding water supply and salinity control: The total number of water supply and salinity control projects implemented is 154/311 projects, reaching 50% of the proposed projects, helping to proactively supply water for nearly 2 million hectares of production.
Along the main rivers, salinity control works were built according to the actual salinity boundary, basically ensuring control of salinity into the fields for average water years (Vam Co River has controlled salinity up to Tuyen Nhon, Hau River has controlled salinity up to Rach Vop, Tien River has controlled salinity up to Cai Lay, on Cai Lon-Cai Be River, proactive control of water sources from the river mouth).
Coastal irrigation systems have been basically completed, serving the goals of salinity control, water supply, and freshwater storage, typically: Nam Mang Thit, Nhat Tao - Tan Tru, Bao Dinh, Go Cong, Long Phu - Tiep Nhat, Quan Lo - Phung Hiep and U Minh Ha irrigation systems.
The water supply canal system is also regularly dredged. In average years, the water basically meets production needs. Except in years of severe drought, when the water source is less than average, some areas still suffer from water shortages.
Some water transfer projects are being prepared for investment to serve difficult coastal areas such as: water transfer system for the South of National Highway 1A, Bac Lieu province, the Tac Thu sluice - estuary project and the West coastal sluices of Ca Mau.
Dry, cracked rice fields due to lack of water in Go Cong Dong district (Tien Giang province). Photo: Quang Sun
- To achieve the irrigation goals set out in the regional planning, the Mekong Delta must build an effective water resource management system, in which the key issues that need to be addressed include:
The Mekong Delta must develop agriculture and aquaculture on the basis of rational and flexible use of Mekong River water resources and the increasing saline intrusion, in accordance with water resource conditions of ecological regions.
The issue of low flow management, ensuring "Water security - Low flow security" is a vital factor for the development, stability and sustainability of the Mekong Delta in the future.
It is necessary to propose adaptive solutions and proactively respond to drought and high salinity years, especially in the current situation of rising sea levels and declining upstream flows; Specifically assess the relationship between flood control and low flows.
For sustainable development, flood control is considered an inevitable direction in the flooded areas of the Mekong Delta. However, it is necessary to pay attention to the flexible conversion of production in areas without flood control to maximize the benefits from floods, the mutual impact of flood control on low flows and saline intrusion (the floods of 2015 and 2016 clearly demonstrated this), the effectiveness and consequences of developing the third rice crop in flooded areas, the impact of flood control on flood ecosystems, the impact of flood control on the stability of river beds, canals, estuaries and coasts, the use of flood water for aquaculture, field sanitation, paying attention to the impact of small and very small floods...;
Proposing a list of priority irrigation works that are suitable for the set goals, have high investment efficiency, harmonize benefits, are suitable for long-term orientation, and meet even the worst scenarios of climate change in the future.
Faced with risks from natural disasters, upstream development and climate change, the issue of water economics must be considered and resolved. Currently, with the instability of natural disasters and climate change, the world is forming two trends in dealing with the water economics problem, with one side being "investment without regret" and the other side being "uncertain climate change scenarios". The water economics problem will have to resolve this contradiction in a harmonious way and regardless of which side it leans towards, it must ensure that the investment is effective.
People in Tan Phuoc commune, Go Cong Dong district (Tien Giang) are getting water from transfer trucks. Photo: Quang Sung
Obviously, in the long term, we cannot let tens of thousands of people face a shortage of domestic water as well as impacts on agricultural production every time there is drought or saltwater intrusion. What are your suggestions for irrigation planning in the Mekong Delta in the coming time?
- The Mekong Delta is facing huge challenges and risks regarding water resources, which are due to: (i) Adverse impacts of climate change (hot weather, declining water resources, changing water resource distribution, rising sea levels, etc.); (ii) Impacts from upstream countries increasing water use (building hydropower plants, increasing cultivated areas, water transfer projects, etc.); (iii) Changes in water use within the delta (increasing cultivated areas, changing production models, requiring better water quality, etc.).
In the future, water resources conditions may worsen, requiring us to have effective response strategies. There are two groups of solutions proposed for water resources management in the Mekong Delta.
One is a group of solutions on construction investment: Completing and upgrading the irrigation systems that have been invested in, ensuring the highest efficiency of the systems. Investing in water supply and water transfer projects for areas with difficulties in water resources. Investing in a number of small-scale decentralized water reservoirs to serve temporarily during times of water shortage and saltwater intrusion.
For upstream areas, it is necessary to consider flood control focal works, reduce investment in small-scale flood control works (small-scale embankments and embankments). Invest in salinity control works along the main river according to the largest salinity line that can penetrate. Complete the sea dyke system and coastal mangrove forests to prevent natural disasters from the sea.
In the long term, continue to research water resource control through large estuary projects, to proactively regulate water resources, reduce saltwater intrusion, and respond to the most extreme water resource scenarios.
Regarding domestic water supply: The Ministry of Construction needs to soon deploy domestic water supply plants from Hau River according to the identified Mekong Delta Regional Planning (3 plants on Hau River, 2 plants on Tien River). Then the water supply for urban areas will be basically guaranteed.
With rural water supply, due to the scattered population in the area, large pipeline systems are difficult to cover, the proposed solution is to develop small water supply stations with water sources suitable for each area (water in irrigation systems, underground water, RO salt water filtration or construction of freshwater reservoirs), combined with people's own water storage solutions.
The second is a group of non-structural solutions such as converting production models, converting crops, and adapting to natural conditions. For freshwater areas: In addition to the scope identified in the Project for sustainable development of 1 million hectares of high-quality, low-emission rice in the Mekong Delta, it is necessary to study the application of science and technology such as water-saving irrigation, advanced irrigation, etc. for areas producing fruit trees, crops, etc. to effectively use water resources.
Coastal areas: In transitional areas that strongly switch to seasonal crop rotation models (shrimp-rice model), aquaculture areas have solutions to ensure water environment and prevent disease spread in water sources.
Strengthen forecasting/early warning work to have solutions to cope with increasingly harsh natural conditions.
Arrange appropriate crop calendar to limit the impact of drought, saltwater intrusion, avoid flood peaks, thereby reducing investment in building irrigation works.
Thank you, Director!
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