Erchong Floodway

Located on the left bank of the Tamsui River in New Taipei, the floodway passes through the districts of Sanchong, Xinzhuang, Wugu, and Luzhou.

[citation needed] The Taipei Basin is historically prone to flooding being located in a humid subtropical climate that can often experience catastrophic typhoons.

The Tamsui acts as the sole hydrological outlet of the basin as it drains freshwater north to the Taiwan Strait, but the river is at a low elevation near sea level and is therefore subject to reverse saltwater flow at high tides several times a month.

After Typhoon Gloria caused significant flooding in Taipei in 1963, the Taiwan government carried out an engineering project to widen the Tamsui River at its narrowest point at Lion's Head Rock, near the present-day Guandu Bridge.

The first phase was completed in 1984, creating an alternate freshwater channel for the Tamsui River on its left bank at times of high water level.