According to Truong Quoc Bao, Head of the Yen Xa Wastewater Treatment Project under Hanoi’s Infrastructure and Agricultural Construction Investment Project Management Board, water is transferred from West Lake to the To Lich River via a dedicated pipeline system.

This pipeline, added to the Yen Xa wastewater treatment system, includes two parallel HDPE pipes with a diameter of D1200, stretching nearly 1.5 km. Water is drawn from Gate A of West Lake, channeled along the existing canal on Cong Do Street, passes through Alley 24 Vo Chi Cong Street, and is then directed into the open canal that leads to the headwaters of the To Lich River.

The system also helps replenish West Lake through Dam Sen and facilitates water discharge when lowering the lake's water level is needed. Bao emphasized that the separate pipeline ensures that clean water from West Lake does not mix with wastewater from the TE3 canal. Meanwhile, all wastewater continues to be routed to the Yen Xa Wastewater Treatment Plant for processing.

As of August 15, construction teams had completed the collection of all 245 wastewater discharge points along the To Lich River. Among them, 63 outlets have had their ground surfaces restored, ensuring that all wastewater is directed to the Yen Xa treatment facility. The plant has now increased its treatment capacity to 200,000 cubic meters per day and night, sufficient to handle the entire wastewater load from the river.

With the water replenishment and regulation dam component in place, treated water with a capacity of 200,000 to 230,000 cubic meters per day and night will be used to fully treat To Lich River's wastewater. By September 20, treated water from the Yen Xa facility will also be discharged into the river.

Together, the clean water from West Lake and the treated water from Yen Xa will create a new continuous flow along the To Lich River, maintaining a discharge volume of approximately 200,000 cubic meters per day. Once operational, the river’s water level is expected to stabilize at 3.5 meters.

Nguyen Van Tho, 51, a lifelong resident of Nghia Do Ward’s Group 23, was present early in the morning to witness the water release. His family has lived by the To Lich River for generations.

“When I was a child, Nghia Do was still part of Tu Liem District. The To Lich River was clear enough to release fish into. Kids in the village used to gather here to fish or swim across the river. Every evening, people of all ages would stroll along the riverbanks,” Tho recalled.

“For nearly 20 years, the river became severely polluted, especially in October and November when the water level dropped, and the smell became unbearable. No one wanted to come near it anymore.”

Tho hopes that with consistent wastewater treatment and the replenishment from West Lake, the To Lich River will return to its former clean state. “We hope to relax by the river again, cast fishing lines, and enjoy the breeze.”

N. Huyen