They kind of said but didn't spell it out, am I reading this right?
This guy was mad because previous park policy was to dredge the river in such a way that he could get into the lake from his dock up river. Park put a new policy in place that the river path will go back to its wild ways, which means now this dude's dock is useless unless water levels are at a certain point. So he decided he would just dig his own path into the lake.