The delta receives almost all of its water from the Indus river , which has an annual flow of the Indus river is about 180 billion m3 , and is accompanied by 400 million tonnes of silt .
The delta receives almost all of its water from the Indus river . 
 The annual flow of the Indus river is about 180 billion m3 , carrying with it some 400 million tonnes of silt .