Complex sentence: Rapids are sections of a river where the river bed has a relatively steep it ranges from 1-8 with 1 being the most navagatable and 8 bring the least gradient, causing an increase in water velocity and turbulence.
Split into simpler sentences: Rapids are sections of a river where the river bed has a relatively steep slope. Its intensity ranges from a scale of 1-8, with 1 being the most navigable and 8 being the least gradient, causing an increase in water velocity and turbulence.