The river diversion, which started in 2012, involved removing components of the river embankment, constructing a series of dams, strengthening the soil and excavating a new canal on the river’s west bank. A new embankment was built across the original river, which was drained and filled with soil. The debris along the tunnels’ routes were removed using piling rigs before tunneling works commenced. To ensure the construction would not pollute the river (which is connected to the Marina Reservoir), the LTA had to maintain adequate hydraulic flows to keep the water clean. After boring through the area, the river was realigned to its original course.