Hanoi revives ‘dead’ rivers: Slow water replenishment could leave To Lich River dry

Editor’s note: Recently, Hanoi’s proposal to spend over 500 billion VND on a project to divert water from the Red River to the To Lich River – aimed at “reviving” the so-called “dead” river – has drawn significant public attention. Through Vietnam Agriculture and Nature Newspaper, experts, scientists, and relevant authorities have analyzed Hanoi’s plan and suggested constructive solutions to help the city government address both immediate and long-term challenges affecting all polluted rivers.

Strong direction from Vietnam General Secretary and Prime Minister

Recently, Deputy Prime Minister Tran Hong Ha has instructed the Hanoi People's Committee to immediately begin replenishing the To Lich River, especially now that 100% of wastewater along the river is being treated at the Yen Xa Wastewater Treatment Plant. He also directed the Ministry of Agriculture and Environment and the Ministry of Construction to coordinate, guide, and support Hanoi in expediting project procedures to “revive” the river. Vietnam Agriculture and Nature Newspaper interviewed Deputy Minister of Agriculture and Environment Nguyen Hoang Hiep regarding this issue.

According to Deputy Minister Hiep, pollution in many rivers has reached critical levels. Some are even referred to as “dead rivers” due to the lack of natural flow and their role as wastewater collection sites.

Beyond supporting ecosystems, daily life, and economic development, rivers also provide water for irrigation. If irrigation water is polluted, clean agricultural products cannot be ensured. That is why authorities are working closely with local governments and relevant agencies to find comprehensive, long-term solutions, aiming for a more systematic and effective approach to river restoration.

Deputy Minister Nguyen Hoang Hiep gave an example of the Bac Hung Hai irrigation system, which the General Secretary and the Prime Minister paid great attention to and directed strongly. The first project that the agricultural sector initiated to address this issue was to build the Xuan Quan Field Pumping Station (in the Xuan Quan sluice area, Van Giang district, Hung Yen province). This is a temporary solution project to supplement water for the Bac Hung Hai river during the dry season, when the water level of the Red River drops too low.

“After the pumping station became operational, we saw a positive outcome. During the water intake period for flooding fields for the 2024–2025 winter-spring crop, we inspected localities in Hung Yen and Hai Duong. All farmers confirmed that this year, the water source was no longer polluted. This is because, before supplying water to the fields, the Xuan Quan Field Pumping Station pumped water from the Red River, pushing the flow of the Bac Hung Hai River forward,” said Deputy Minister Nguyen Hoang Hiep.

However, he emphasized that this is only a temporary solution to address the immediate problem. In the long run, more sustainable measures must be taken to ensure that rivers are no longer “dead” and that they no longer serve as dumping grounds for polluted waste.

Using pumps to replenish To Lich River: Only a temporary solution

Deputy Minister Hiep also discussed a second key issue. Recently, during a working session with Hanoi, General Secretary To Lam instructed the city not only to address the pollution of the To Lich River but also to restore all rivers to their original state. In response, Hanoi has submitted a plan to the Prime Minister to supplement the To Lich River with water from the Red River through pumping. The Ministry of Agriculture and Environment has actively collaborated with Hanoi to develop solutions for this initiative.

He acknowledged that there are differing opinions on how best to restore a river like To Lich. “That’s understandable, as reviving a river is no simple task,” he said. “The first step is to collect and treat wastewater to prevent polluted water from flowing into the To Lich River. Hanoi is already working on this, and the wastewater collection project at Yen Xa Wastewater Treatment Plant (Thinh Liet Commune, Thanh Tri District) is expected to be completed by April 30, 2025.”

The next challenge is how to maintain the water flow. “Once domestic wastewater stops flowing into the To Lich River, it will no longer be a ‘dead’ river, but it risks becoming a dry river. A dry river can lead to serious issues like subsidence, accumulated dirt, and even greater environmental hazards than a polluted river. This is why it is urgent to replenish the To Lich River’s water through pumping,” Deputy Minister Hiep stressed.

Hanoi is proposing a plan to build a pipeline through Vo Chi Cong Street, then bring water into a settling lake and replenish the To Lich River. “I think this is a temporary solution that is suitable for 10-15 years, but in the long term, the city cannot spend money forever to pump water because it is very expensive,” said Deputy Minister Nguyen Hoang Hiep.

Build three dams on the Red River, Da River, and Duong River to restore the original state of Hanoi’s rivers

Deputy Minister Nguyen Hoang Hiep emphasized that to address the long-term issue – following the General Secretary’s directive to “restore the original state of Hanoi's rivers” – a fundamental solution is needed.

“The first approach we considered is constructing dams on the Red River system. In the 2021–2030 Natural Disaster Prevention and Irrigation Plan, with a vision to 2050, we proposed two dams: one on the Red River near Xuan Quan sluice and another on the Duong River near Long Tuu sluice. Additionally, if we build a third dam on the Da River at the Trung Ha Bridge area (Ba Vi District, Hanoi), we can fundamentally resolve the issue of self-flowing water for the Nhue, Day, To Lich, Tich, and Bac Hung Hai rivers. Only when there is a stable, self-sustaining water source can we prevent sedimentation and restore these rivers to their natural state,” he explained.

Regarding investment costs, Deputy Minister Hiep noted that there are multiple ways to mobilize funding, including public-private partnership (PPP) models. “Businesses can invest in building the dams, and in return, the State can allocate land on both sides of the river or integrate these projects with other infrastructure developments,” he suggested.

However, he stressed that ensuring a clean water supply is just one part of the solution. Hanoi must also continue implementing wastewater collection and treatment measures to prevent pollution from re-entering the rivers.

Addressing concerns about the appropriate water flow needed to sustain the To Lich River, Deputy Minister Hiep acknowledged that determining the optimal flow rate (in cubic meters per second) is a complex issue. “This is a crucial question for Hanoi because it directly impacts water flow management and investment scale," he said.

He provided an example: "The Xuan Quan Field Pumping Station was built with a capacity of 16 m³/s to address an urgent need. If we wanted to completely flush out the Bac Hung Hai River, we would need a much larger pumping station with a capacity of several dozen m³/s. However, since it primarily serves agricultural fields, constructing such a large-scale station is not feasible."

Therefore, he thought that Hanoi building a field pumping station of 3-5 m³/s to supplement water for To Lich River is also acceptable, but if it is fully built to push the water source like a natural river, it may have to invest in a pumping station of up to 16-20 m³/s.

According to Deputy Minister Nguyen Hoang Hiep, there are two ways to make a sedimentation pond before bringing Red River water into To Lich River.

The first way is to lead water into some lotus ponds in Tay Ho district as Hanoi is proposing. The second way is to pump water directly into To Lich River and build a dam in Hoang Quoc Viet area to act as a settling pond, and only need to dredge alluvium in that cell, because the project only needs to add a flow of 3m³/s, to solve the situation, it is completely acceptable.