Complex sentence: 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.
Split into simpler sentences: 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.