The water diversion gates at the South Main Canal and North Main Canal of the Chianan Canal connect the Wushantou Reservoir's leading channels to these two main lines. They serve as crucial hubs for regulating and distributing water to both lines, supplying 64,000 hectares of agricultural land in the Chianan Irrigation District and providing domestic and industrial water for 2.5 million people in Tainan and Chiayi Counties and Cities.