Mekong Delta: Drought, saltwater intrusion cause subsidence, water shortage

Urgent measures are being implemented to address the impending saltwater intrusion in the region.

Estimated damages of over VND9 billion

In late February 2024, temperatures have continuously soared in the Southern region, with some areas reaching as high as 38 degrees Celsius. Concurrently, water levels in the river networks dropped significantly, resulting in extensive saltwater intrusion into inland areas.

In the coastal communes of Thanh Phu District (Ben Tre Province), although it is just the beginning of the dry season, many local households have already had to buy treated fresh water for use as the groundwater from drilled wells has become saline-contaminated. Living more than 20km from the coast, Nguyen Thi Sau, a resident in Tan Phong Commune, explained that water supplied by the factory has become salty, forcing residents to purchase treated fresh water at a cost of VND100,000 per cubic meter for cooking, bathing, and cleaning purposes.

According to the Ben Tre Province Hydro-Meteorological Station, the 2023-2024 dry season has seen saltwater intrusion starting earlier, penetrating further and lasting longer, compared to the average of the last ten years. Saltwater intrusion commenced as early as November 2023 and is expected to persist until May 2024. Currently, along the main river branches in Ben Tre, saltwater intrusion has occurred at varying levels, with some areas experiencing salinity levels exceeding 3 per mille, penetrating inland for over 40km along the main river channels.

Likewise, in the freshwater conversion zone of Tran Van Thoi District in Ca Mau Province, the severe effects of drought are causing significant land subsidence and disrupting transportation routes. Many canals in the area are drying up, rendering waterway transportation inoperable. As a result, farmers in the region are compelled to sell rice at prices lowered by VND300-700 per kg due to increased transportation costs using motorcycles. The latest statistics reveal that the drought-induced land subsidence has led to estimated damages exceeding VND9 billion. This figure continues to escalate daily.

According to Mr. Do Van Su, Head of the Department of Agriculture and Rural Development in Tran Van Thoi District, this year, the district has grown rice on over 28,950 hectares, with more than 11,000 hectares already harvested. Around 2,000 hectares of rice and over 282 hectares of other crops are forecasted to be affected by saltwater intrusion. "To minimize the damage to vegetable crops for local residents, the authorities have collaborated with the Department of Agriculture and Rural Development to conduct training sessions and offer technical guidance on vegetable cultivation techniques under water scarcity conditions. Simultaneously, efforts are underway to encourage the community to utilize water resources efficiently for irrigation," Mr. Do Van Su further informed.

According to the Department of Agriculture and Rural Development of Tien Giang Province, which boasts the largest area of fruit trees, spanning over 86,000 hectares, around 35,000 hectares of fruit trees suffer direct affect by saltwater intrusion this year. The most vulnerable and requiring protection are the areas along the Tien River, from Phuoc Thanh Commune (My Tho City) to Hoa Hung Commune (Cai Be District), with durian trees predominantly occupying 22,000 hectares.

In light of the current situation, Mr. Vo Van Men, Director of the Department of Crop Cultivation and Plant Protection of Tien Giang Province, said that the agricultural sector has advised farmers to adapt by shifting and restructuring cropping seasons. Six culverts on Provincial Road 864 in Western districts of the province have been completed. When saltwater intrusion becomes severe, these culverts will be closed, and irrigation for vegetables and fruit trees will rely on water from the Nguyen Van Tiep canal.

Proactive freshwater storage

According to the assessment by the Southern Institute of Water Resources Research, the 2023-2024 dry season is predicted to be among the years with low water levels, with saltwater intrusion occurring earlier and deeper than the average of previous years. The highest salinity is expected in February and March, with abnormal water retention potentially causing saltwater intrusion to reach depths of 55-70km. Hence, local authorities need to proactively devise suitable measures to combat saltwater intrusion, taking into account the region's conditions.

With such extensive saltwater intrusion, approximately 56,260 hectares of rice fields in the provinces of Long An, Tien Giang, Ben Tre, Tra Vinh, and Soc Trang face the risk of water shortage. Additionally, saltwater intrusion may impact around 43,300 hectares of fruit tree cultivation areas in Tan Tru District (Long An), Cho Gao and Go Cong Tay districts (Tien Giang), Mo Cay Nam and Chau Thanh districts (Ben Tre), and Ke Sach District (Soc Trang). Furthermore, it poses a risk of water scarcity for dispersed households and centralized water supply systems utilizing surface water along coastal areas in various locations such as Bac Lieu, Soc Trang, Ben Tre, Tra Vinh, and Vinh Long.

To proactively address the situation, Mr. Nguyen Thanh Truyen, Director of Long An Province's Department of Agriculture and Rural Development, has instructed local authorities to closely monitor water quality and saltwater intrusion in rivers, canals, and channels. They are also urged to stay updated on weather forecasts, hydrological information, and water resources provided by central and provincial agencies, ensuring that agricultural and household water supplies remain unaffected. Additionally, residents are advised to use water for irrigation efficiently and economically, avoiding intake from saline-affected areas to prevent pollution of inland water sources. Farmers are encouraged to plant crops according to local recommendations, prioritizing fragrant, high-quality, short-term rice varieties, as well as drought-tolerant and salt-tolerant ones, to facilitate irrigation or encourage crop structure conversion.

Mr. Tran Ngoc Tam, Chairman of the People's Committee of Ben Tre Province, shared that local authorities have advised residents to proactively store fresh water for household use and irrigation. Relevant departments have been directed to closely monitor the situation to ensure timely response plans are in place.

Associate Professor – Dr. Le Anh Tuan, former Vice Director of the Research Institute for Climate Change (Can Tho University), shared that the institute has conducted field surveys in several coastal provinces of the Mekong Delta. It has been observed that since mid-February 2024, the Southern region has been experiencing severe heatwaves. Coastal provinces have also encountered strong winds, leading to accelerated water evaporation and exacerbating drought conditions.