Nearly its entire length of 1,150 kilometres (710 mi) runs within the isolated, mountainous and ethnically diverse province of Guizhou.

It then bends north, west and south in a 300 km (190 mi) reach called the Yachi, and receives the Nanming River from the right.

After the Yachi reach, the Wu makes a broad arc northeast through central Guizhou, picking up fifteen major tributaries including the Yu, Furong and Ya Rivers and flowing through several large hydroelectric dams.

[5] Aside from producing power, dams on the Wu River also provide flood control and hydraulic head for irrigation operations.

[6] The lower reaches of the river are heavily polluted because of poor sewage systems and dumping of agricultural waste – so much that it is not even considered suitable for irrigation and industrial purposes.

The lower 480 kilometres (300 mi) of the river were dredged of sediment and hundreds of sets of rapids were destroyed by explosive charges.