Complex sentence: This is where it flows between the two roads named Green Lanes which is what the river is named after, before running into the the Hogsmill Open Space before meeting the confluence with the Hogsmill Stream.
Split into simpler sentences: This is where it flows between the two roads named Green Lanes (the river is named after the roads). It runs into the the Hogsmill Open Space before meeting the confluence with the Hogsmill Stream.