In recent years, Shanghai's Baoshan district has completed several first-flush rainwater storage tanks, helping improve local water quality. Two more are now nearing completion.

Situated near the Shanghai Baoshan Science Park, the underground structure for the new storage tanks is now in place, and equipment installation is underway.

According to the Baoshan District Drainage Management Office, a first-flush storage tank captures runoff generated by the first 5 millimeters of rainfall. After the rain stops and the external drainage network has sufficient capacity, the stored rainwater is pumped into the sewage system and sent to a wastewater treatment plant for processing, thereby improving the regional water environment.

The new storage tanks have a combined capacity of 18,000 cubic meters and will serve an area of approximately 3 square kilometers. Once completed, they are expected to significantly improve the water environment in the Taopu River area.

As a core component of both sponge city infrastructure and urban drainage systems, first-flush storage tanks are designed to collect and temporarily store highly polluted runoff from the early stages of rainfall, typically during the first 15 to 30 minutes. They serve two primary functions: reducing pollution entering waterways and mitigating peak flows to help prevent urban flooding.

Source: Shanghai Baoshan Media Center