The effects of siltation of the Da Do riverbed

Leaders of Da Do Irrigation Works Exploitation Company Limited coordinated with An Lao commune to inspect the location affected by Da Do river sedimentation.

See clearly the harm and cause

Some people in Kien Hung commune have just finished harvesting the winter-spring rice crop, preparing to move on to the 2025-2026 winter-spring crop. People are worried because every spring crop, production faces many difficulties, mainly due to prolonged drought and saltwater intrusion, causing difficulties in water sources for production. Ms. Nguyen Thi Dao, in Kien Hung commune, said that in the dry season, saltwater intrusion deep into the Van Uc river makes it impossible to get water for production. Getting fresh water from the Da Do river is difficult due to low water levels in the river, and in the rainy season, prolonged drainage causes local flooding.

Not only Kien Hung commune, some other areas in An Lao, An Hung, Phu Lien, An Lao, An Khanh communes... also face difficulties due to the drainage situation along the Da Do river axis.

The reason is that recently the Da Do River has had many sedimentation points, narrowing the flow, reducing the drainage volume and prolonging the drainage time, causing local flooding. Some large sedimentation points also obstruct the flow of domestic wastewater, causing waste to accumulate, seriously affecting the quality of water sources and water intake of factories.

According to the review of the Hai Phong Da Do Irrigation Works Exploitation Company Limited, recently on this river, 9 local sedimentation points appeared at some locations of flow diversion, narrowing the flow. The sedimentation locations, shallow and full, with an average width of 30m ÷ 80m, the average sedimentation elevation from (+0.3) ÷ (+0.7) have reduced the water storage capacity of the river. Specifically, the section of the Cau Nguyet water plant (from K20+250 to K21+350) (in An Khanh commune) has accumulated into a sedimentation strip L=1,100 m long, the average sedimentation elevation from (+0.4 ÷ +0.75) m, the sedimentation width from 50÷70 m. The sedimentation situation causes flow blockage, reduces the drainage capacity, slows the flow rate, affects the quality of water sources and the ability to take water into the Cau Nguyet water plant.

Or the section from Cau Tre culvert to Khuc Gian culvert (From K4+100 to K5+450), belonging to An Truong and An Lao communes, the left bank of the river is silted up to 1,350 m long, silted up to (+0.35÷+0.5) m, silted up to 50÷60 m wide. This is an important location for fast water supply and drainage for the two canals Khuc Gian and Ngoc Chu, especially for flood prevention and control for the above communes. The silting reduces the drainage capacity of the canals, causing local flooding for the communes during the rainy and stormy season, affecting agricultural production...

Leaders of the Department of Agriculture and Environment inspected the sedimentation site on the Da Do River.

Short-term and long-term solutions

The Da Do River system has the task of maximizing the water source through Trung Trang sluice (An Truong commune) and draining water to Co Tieu sluice (Kien Hung commune) to flush out salt and acidity, ensuring the quality and quantity of water for production and people's lives. The system also plays a role in drainage, preventing natural disasters and floods, contributing to ensuring social security.

Therefore, in the face of the above-mentioned sedimentation points, the unit has applied the main solution of dredging the sedimentation points, building banks to increase the flow, taking advantage of the time to take water, storing water in the system to ensure quality and reserves for production. In the dry season, the saline intrusion situation is more complicated. Therefore, to overcome this phenomenon, from 2024, Da Do Irrigation Works Exploitation One Member Co., Ltd. must always take advantage of the time to increase the ability to quickly take water into the Da Do River to push salt water and polluted water out of the system.

In the long term, Chairman of Da Do Irrigation Works Exploitation Company Limited Do Van Trai said that it is necessary to synchronously plan the Da Do River into a freshwater storage river for socio -economic development, at the same time, dredge the entire Da Do Riverbed; build a dam on both sides of the Da Do River to elevation +2.5 with a total length of 100 km to ensure water storage capacity; build sluices on the Da Do River to close the riverbank, prevent waste and wastewater in level 1 canals to minimize water pollution, and protect water quality in the Da Do River. Therefore, it is necessary to have the attention and facilitation of the city and central ministries and branches...

HO HUONG

Source: https://baohaiphong.vn/tac-hai-long-song-da-do-bi-boi-lang-528969.html