Complex sentence: Several other smaller waterways, both natural and man-made, drain into the Styx River, which flows through Belfast, Marshland and Spencerville before it reaches Brooklands where it flows into the Brooklands Lagoon and from there into the Waimakariri River.
Split into simpler sentences: Several other smaller waterways, both natural and man-made, drain into the Styx River. The Styx River flows through Belfast, Marshland and Spencerville before it reaches Brooklands and flows into the Brooklands Lagoon and from there into the Waimakariri River.