The Hanja River originates near Quilengues, has a watershed area of 2400 km2, a guideline of 148 km.
It flows into the left bank of the Coporolo river, 6 km upstream from the mouth of the Impulo river.
Its mouth, very close to the mouth of its twin brother Impulo, gives the Coporolo river an interesting point for future rainwater supply in other words, a dam, which can retain the waters of the 3 rivers: Coporolo, Hanja and Impulo.