Taipei Flood Mitigation Project. During torrential rains, when the water stage inside the dike (land) is higher than that outside the dike (river channel), the gates are opened and flood water is discharged into the river channel by gravity. And when the river level is higher than the water stage inside the dike, the gates are closed and the flood water is pumped into the river channel to prevent further flooding. With 33 water gates, the Taipei Flood Mitigation Project has the most water gates of all flood control project.