"Water flow" on the Kern river is measured in cubic feet per second (cfs.) Lets say the water flow gage displays 1000 cfs in the last column to the right:
NF Kern
at
Kernville

7.5  1000
This would be like holding a string across the river and said, "one thousdand and one"", it takes about a second of time for 1000 basketballs to pass under the string that is stretched across the river. But it's water instead. Eagle Rafting season starts when the water flows are over 700 cfs. during sometime in April, and ends when the water flow goes below 350-400 cfs., around the July 4th weekend. But when the flows are up the water can last into October!