The middle route project of South-to-North Water Transfer Project uses the gap between the Taocha outlet of Danjiangkou Reservoir and the provinces and cities to realize the whole line of self-flowing water delivery. Because all trunk lines are underground pipe culverts after entering Beijing, in order to meet the water supply demand of Beijing section, China has built the only high-flow and high-lift pressurized pumping station in the middle line in Huinanzhuang, Fangshan District, Beijing, where South Water enters Beijing.
There are two water supply modes in Huinanzhuang Pumping Station: small-flow gravity gravity gravity water delivery and large-flow water pump pressurized water delivery. Combined with the urban demand, when the water supply flow is less than 20 cubic meters per second, the Nanlai River flows through the pumping station to save energy. On the contrary, start the water pump unit to deliver water under pressure and improve the water supply capacity.