Complex sentence: However, it has changed its course and in its lower reaches most of the water flows into the Mundeswari River, which combines with other rivers and finally most of the Damodar water flows into the Rupnarayan River.
Split into simpler sentences: However, it has changed its course, and in its lower reaches most of the water flows into the Mundeswari River, which combines with other rivers. Finally most of the Damodar water flows into the Rupnarayan River.