well ok - but why is this a problem? It rains here A LOT!
I see it more as civil situation than criminal.
Up here in Washington we can’t water out of rivers and creeks without explicit rights, either; if there were no restrictions then upstream users would store or use water as they saw fit and without regard to downstream rights. There have been wars over similar water-rights issues.
This user was not able to differentiate between precipitation which fell on his own property and that which flowed from offsite in the stream. He tried to make an argument that existing dams on the stream diverted water to his property which made it available to him for storage but this did not fly with the latest court.