Hanoi is racing to revive its most polluted rivers - such as the To Lich, Kim Nguu, Set, and Lu rivers - by combining dredging, wastewater redirection, and digital monitoring technologies. The goal: complete the collection and treatment of all wastewater discharged into the To Lich River and restore its flow by August 30, 2025.

A silent crisis in the heart of the capital

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To Lich River before rehabilitation. Photo: Doan Bong

Rivers and lakes in Hanoi play a vital role in water supply, climate regulation, and urban aesthetics. Yet decades of unchecked urbanization have turned many of these rivers into stagnant, blackened canals. The root cause? Rapid urban development outpacing infrastructure, compounded by public littering and illegal encroachments.

According to Nguyen Dinh Hoa, Deputy Director of the Hanoi Department of Agriculture and Rural Development, untreated waste from residential and industrial zones has long been discharged directly into rivers.

Compounding the issue is the significantly lowered water level in the Red River and Thai Binh River systems - at times dropping up to 14 meters below design levels - rendering gravity-fed systems ineffective.

Many legacy water control structures from the French colonial period or the 1960s–70s are now obsolete. To maintain flow, mechanical pumping has become essential.

Smart solutions for dead rivers

At the recent forum “Solutions for Reviving Dead Rivers” organized by the Hanoi People’s Committee and Tien Phong newspaper, experts emphasized the need for systemic, smart interventions.

Hoang Duong Tung, former Deputy Director General of the Vietnam Environment Administration, applauded Hanoi’s strong commitment but urged digital transformation.

He advocated adopting GIS-based wastewater tracking systems that assign accountability down to the ward level. Smart meters should be mandated for industrial producers discharging over 10m³/day, enabling real-time monitoring of wastewater volumes and discharge quality.

“All sensors must be linked for second-by-second monitoring. This data feeds into a live GIS map showing discharge sources by sub-basin. This is how smart river governance should work,” Tung stated.

To Lich River: A case study in integrated restoration

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Mr. Hoang Duong Tung, former Deputy Director General of the Vietnam Environment Administration. Photo: Duy Pham

Le Dinh Du, Head of Drainage Infrastructure at the Hanoi Department of Construction, shared details of the To Lich River rehabilitation strategy.

The city is carrying out a comprehensive dredging operation while collecting all waste outflows along the river.

These will be diverted to the Yen Xa Wastewater Treatment Plant, where treated water will then be reused to rehydrate the river.

Two key inflow sources will be used to restore flow: treated effluent from the Yen Xa plant and pre-treated water from West Lake, channeled through a regulatory gate at Tay Ho ward. A specially designed weir at Quang Bridge will maintain optimal water depth for steady flow.

All infrastructure works related to waste collection and riverbed restoration must be completed by August 30, 2025.

Towards a resilient blue infrastructure

Experts say the revival of urban rivers must not stop at basic engineering.

A long-term solution involves integrating rivers into Hanoi’s green infrastructure, strengthening flood control, improving biodiversity, and reconnecting communities with waterways.

Crucially, institutional reform and smart technologies must go hand in hand with public education and enforcement.

The resurrection of Hanoi’s rivers is not merely a sanitation effort - it’s a blueprint for how a megacity can turn ecological decay into urban renewal.

N. Huyen