I went to the Peak District yesterday to do my fieldwork (I'm self teaching but left it a bit late) and I measured the river velocity, load particle size and channel depth against the bradshaw model. I'm confused though on how to work out how the velocity changes downstream? I measured the time it took for an orange to get from one point to another in 10m, 5 times, and have the average velocity. But how do I know if it has changed downstream? Please help!