Forecast of salinity on rivers in the South Central region

On March 27, the Central and Central Highlands Institute of Water Resources Research reported that last week (March 21-27) in Quang Nam province, the water level at dams was higher than the previous week and met the prescribed water level requirements. Regarding salinity, the monitoring points on the Thu Bon River branch (old Cau Lau bridge, Cam Dong arch) and the Vinh Dien River branch (pumping stations) were not affected by salinity.

Checking water quality on An Trach irrigation system. Photo: PV.

In Da Nang City, the salinity on the Vu Gia River branch is low, the Tuy Loan and Mieu Ong pumping stations have not been affected by salinity; the salinity upstream of the Cau Do water plant has increased compared to last week, but still ensures the requirements for domestic water supply, the corresponding value ranges from 0.02‰ - 0.08‰.

The Central and Central Highlands Institute of Water Resources calculates that next week (from March 28 to April 3), the indicators at 6 monitoring locations will all meet the requirements for irrigation water quality for agriculture, the salinity at the locations will tend to decrease slightly compared to last week, especially at the upstream location of Cau Do, the highest salinity can reach 0.35‰. Therefore, during the operation of the An Trach irrigation system, relevant units need to pay attention to:

- The Department of Agriculture and Environment of Quang Nam province and Da Nang city need to pay attention to directing the Irrigation Sub-Department and the Irrigation Exploitation Company to continue monitoring meteorological and hydrological forecast information and developments of saline intrusion and water quality, proactively adjusting timely and effective response solutions to supply water for winter-spring crops.

- For Da Nang City and Quang Nam Province Irrigation Exploitation Company Limited, it is necessary to strictly manage water resources and ensure irrigation for areas in the system; direct units to monitor water level developments, closely follow the tide schedule, water discharge operation schedule of hydropower plants as well as saline intrusion developments to develop an operating plan to ensure safe water supply for the winter-spring crop.

In addition, units need to closely coordinate with water cooperative organizations to strengthen field inspection and regulate water flow on irrigation canal systems to provide timely water for production.

The salinity forecast at Cau Do location from March 28 to April 3 is likely to fluctuate from 0.02‰ to 0.27‰, some times exceeding 0.25‰ (250mg/l). Therefore, it is recommended that Cau Do water plant needs to monitor the salinity changes at this location to have an operational plan according to regulations. At times when the salinity is in the range of 200÷1000mg/l (0.2‰ ÷1.0‰), it is necessary to adjust the flow through the water intake of the plant and take the maximum possible water from Vu Gia river from the pumping station at An Trach dam. At the same time, proactively develop reasonable operational plans to ensure safe water supply next week.

- Reservoir owners operating hydropower plants must comply with the inter-reservoir operation process in the Vu Gia - Thu Bon river basin approved by the Prime Minister and Article 28 of the Law on Water Resources to support the work of preventing drought and saltwater intrusion in downstream areas. At the same time, closely coordinate with the Department of Agriculture and Environment of Quang Nam province to develop and agree on a plan to release water for power generation in batches associated with the water demand for daily life and agricultural production in the winter-spring crop of 2024 - 2025 in the downstream area, ensuring effective water use.

Source: https://nongnghiep.vn/chu-dong-cac-giai-phap-de-dam-bao-nuoc-tuoi-cho-cay-trong-vu-dong-xuan-d745232.html