"It's an unbelievably picturesque scene," said Thu Ha, 25, from Tu Lien ward.

On the morning of 26/8, on her way to work, Ha was astonished to see a different version of the river. The water level was high, almost reaching the embankment, and the color was a clear blue. The usual floating debris was gone, replaced by fresh green grass along the banks. Ha stopped to take some photos to share this unusual sight with her friends.

The To Lich river, near Kim Giang - Khuong Dinh, unexpectedly turned clear and blue after heavy rain from the night of 25/8 to noon on 26/8. Photo: Dung Sky

The To Lich river, near Kim Giang - Khuong Dinh, unexpectedly turned clear and blue after heavy rain from the night of 25/8 to noon on 26/8. Photo: Dung Sky

Sharing the same sentiment, Duc Dung, a resident living near the To Lich river in the Kim Giang area, also braved the rain to capture the scene. He noted that the water level was similar to the historic flood of 2008, about one meter from the railing along the bank. The water flowed swiftly towards the Yen Xa downstream, washing away the usual murky color and debris.

According to Dung, since the beginning of 2024, the To Lich river has "changed its appearance" several times after heavy rains, although not as dramatically as today. He believes this is not only due to the large volume of rain diluting and washing away pollution, but also thanks to the city's initiatives. Recently, several sections of the river have been dredged, some major discharge outlets have been closed, and notably, the Yen Xa wastewater treatment plant has begun operation.

"In the next few days, when the water recedes, the dark color might return, but it will be less severe than before," Dung said.

The To Lich river turned clear and free of debris on the morning of 26/8. Photo: Dung Sky

The To Lich river turned clear and free of debris on the morning of 26/8. Photo: Dung Sky

Explaining the phenomenon of the To Lich river turning clear, a representative of the Hanoi Drainage Company said this typically occurs during the northern rainy season (from May to October). Continuous heavy rain dilutes and improves the river's water quality. Additionally, water from West Lake is also released into the To Lich river.

"The release schedule isn't fixed, depending on rainfall and the actual water levels of the river and lake to ensure safety and prevent flooding in the surrounding areas," the representative said.

The To Lich river near Kim Giang - Khuong Dinh on the morning of 26/8. Source: Dung Sky

However, the To Lich river's temporary clarity after heavy rain is only a short-term solution. In the long term, Hanoi is implementing several comprehensive plans to revitalize the river.

In early 2025, the city assigned the Department of Construction to research a plan for regular water supplementation from West Lake. Looking further ahead, a project to draw water from the Red river via Vo Chi Cong road is also being studied to ensure a stable water source for both the To Lich river and West Lake.

The biggest obstacle to cleaning the To Lich river is wastewater treatment. According to a report by the Department of Construction in February, over 80 discharge outlets still release wastewater directly into the river. After 8 years of construction, the Yen Xa wastewater treatment plant, with a designed capacity of 100,000 m3 per day, has been in trial operation since 12/2024, contributing to collecting a large amount of wastewater. However, the treated water is discharged into the Nhue river downstream, leaving the To Lich river depleted.

Concurrently, comprehensive dredging of the riverbed is also being accelerated. The Hanoi Drainage Company has essentially completed dredging nearly 60,000 m3 of mud in August.

The To Lich river with its usual jet-black water and pungent odor. Photo taken in early 7/2025. Photo: Viet An

The To Lich river with its usual jet-black water and pungent odor. Photo taken in early 7/2025. Photo: Viet An

Having moved to Nguyen Khang street in Yen Hoa ward over six months ago, Thuy Phuong, 21, witnessed this sight for the first time. Previously, the Ha Tinh native had to wear two layers of masks whenever she went outside. Despite living next to the river, she never dared to open her windows for fear of the stench entering her room.

But since the morning of 26/8, Phuong has opened all her windows to welcome the fresh, clean air. From her second-floor balcony, she can admire the clear blue river, a stark contrast to its usual haunting blackness. The young woman plans to take a walk along the riverbank when the rain stops in the afternoon, something she had never considered before.

"I hope the river will soon be truly revived, so that this blue is not just a temporary beauty after the rains," Phuong expressed.

Quynh Nguyen