He’s not damming a creek. He’s doing something that was done for centuries. He’s collecting rain.
The EPA is using his case as a test case to argue that citizens only have right to the water they are given.
Where do you think creeks and rivers come from? That they appear by magic?
Rainwater is a key source of most running waters.
Diverting rainwater into multimillion gallon reservoirs is identical in effect to damming up a creek.