Gradient
The gradient of a river is measured by the number of feet it drops over the course of a mile. This is typically calculated for a given section of river by taking the total drop and the total length of the run for an average drop per mile.
Volume
The volume of a river is measured in cubic feet per second(cfs). CFS is determined by calculating the number of cubic feet of water that passes a single point on a river over the course of a second.
Temperature
The temperature of a river can change relative to its depth, source, and time of year. Rapids also serve to stir up the river and provide a more uniform temperature.