boosting acerage

I was looking at changing water flows of a river or stream illegelay and found this guy who did just that.
A farmer has pleaded not guilty to charges he rerouted parts of the Wind River to add 300 acres to his property.
How can a farmer use as much water as he was doing, or where was it going. Now the river is scared for life it is no longer in the natural stream bed. This can be dissasterous for people down the drainage.