Before the drought is over, farmers in Nghe An are worried about saltwater intrusion.
(Baonghean.vn) - While the lack of water and electricity for production has already prevented many localities in the province from cultivating crops, now there is a situation where the water is contaminated with high levels of salinity, meaning that even with water available, it cannot be pumped for irrigation because it would kill the crops.
Present at the Rum River, a branch of the Lam River flowing through Chau Nhan commune, Hung Nguyen district, on the morning of June 23rd, our reporter observed that the water level in the river was very low, estimated at about 1 meter, the riverbed was completely shallow, and people could easily wade across it.
The Rum River provides irrigation water for many communes in Hung Nguyen district such as Chau Nhan, Hung Loi, Hung Phuc, Hung Nghia... The highest water level in this river can reach 7 meters (when the water touches the bridge), however, from May until now, even at the highest tide, the water level only reaches 2-3 meters, insufficient for irrigating crops. Many pumping stations in the area have also significantly reduced their pumping time due to the lack of water.
However, currently, the people of Chau Nhan commune and neighboring areas are facing a new worry: saltwater intrusion. The salinity levels in the water have exceeded permissible limits, leaving farmers in a dilemma: they have water but dare not pump it for irrigation because if they do, the rice plants will wither and die immediately.
The Hung Chau pumping station, belonging to the Hung Nguyen Irrigation Enterprise, is the largest pumping station in the district, with 6 horizontal shaft pumping units (capacity of 1,000 m³).3/hour/machine) and 8 vertical shaft units (capacity 8,000m³)3(per hour/per machine). This pumping station has three main functions: drought prevention, flood control, and water source creation, responsible for irrigating nearly 1,000 hectares of rice fields in the dike-side communes of Hung Nguyen district. However, since the water source was affected by saltwater intrusion, irrigation pumping has not been as efficient as before.
Mr. Le Van Hung, Deputy Head of Hung Chau Pumping Station, shared: “From mid-June until now, the salinity level measured daily in the Rum River has fluctuated between 2 and 3 parts per thousand. Meanwhile, the permissible level for irrigating crops is below 1 part per thousand. Only when the tide rises does the salinity decrease slightly; when the tide recedes, the water becomes saline again. Therefore, it is impossible to pump water for irrigation because the plants will die faster than during drought conditions.”
“From May until now, the water level has been low, and the rotating power outages have interrupted irrigation pumping. The pumps are powered entirely by the grid, so diesel pumps or makeshift generators are ineffective. Now the water is also saline, leaving no other way to irrigate and save the summer-autumn rice crop at this time,” Mr. Hung emphasized.
Salinity intrusion is not only occurring in Hung Nguyen district, but also in Nghi Loc district. Particularly in the Cam River system, from the downstream of the Cam River bridge (N5 road) down to the Nghi Quang sluice gate, salinity levels exceed 1 part per thousand, making irrigation impossible for crops.
On June 22nd, Nghi Loc district issued Official Document No. 1805/UBND-NN regarding the implementation of measures to combat drought and saltwater intrusion into inland areas. Accordingly, the Provincial People's Committee authorized Nam Irrigation Company Limited to construct a temporary dam to block the Cam River at the N5 bridge (Nghi Thuan commune) and to conduct rotational pumping between localities: From 7 PM on June 21st, 2023 to 7 PM on June 26th, 2023, pumping stations along the Thap Canal (Nam Dan, Hung Nguyen) will stop pumping to divert water to the Gai Canal to improve the water supply for Nghi Loc district and push back saltwater intrusion into the system.
Therefore, Nghi Loc district has instructed localities along the Cam River with pumping stations from the N5 bridge down to the Nghi Quang sluice gate to absolutely refrain from pumping water for production purposes because the salinity level has exceeded 1 part per thousand.
Localities along the Cam River, Gai Canal (from Highway N5 upwards), and Khe Cai Canal are mobilizing maximum manpower, machinery, and equipment to operate pumping stations managed by the communes and coordinating effectively with the Irrigation Enterprise to operate the Enterprise's pumping stations to irrigate rice crops, making the most of the improved water resources when temporary dams are built on the Cam River and during the period when Nam Dan and Hung Nguyen districts cease pumping. Before and during pumping, the salinity of the water source must be regularly checked, and pumping must absolutely not be done when the salinity exceeds the permissible level.
Reportedly, Nghi Loc district has planned nearly 6,000 hectares for this year's summer-autumn crop; however, the risk of drought and saltwater intrusion is a major concern, especially in localities such as Nghi Thuan, Nghi Hung, Nghi Yen, Nghi Tien, Nghi Thiet, and Nghi Quang...
According to some irrigation officials, saltwater intrusion is very difficult to manage, and there are only two ways to mitigate it. One is to wait for rainwater, which will reduce the salinity level in the water. The other is that water flowing from upstream will also help reduce salinity in downstream areas; however, this is highly unlikely because water levels in upstream rivers and hydroelectric reservoirs are currently very low. Therefore, the most feasible way to reduce salinity is to rely on heavy rainfall.
For this year's summer-autumn rice crop, Nghe An province will plant 81,000 hectares. This production season is expected to face numerous difficulties and challenges. Temperatures are generally higher than average, while rainfall is significantly lower than in previous years. Water levels in reservoirs, rivers, streams, and key infrastructure are low, and saltwater intrusion is increasing. It is estimated that over 6,500 hectares across the province are at risk of drought and water shortage.
