Complex sentence: The Brahmaputra Valley in Assam is approximately 80 to 100 km wide and almost 1000 km long and the width of the river itself is 16 km at many places within the valley.
Split into simpler sentences: The Brahmaputra Valley in Assam is approximately 80 to 100 km wide and almost 1000 km long. The width of the river itself is 16 km at many places within the valley.