If it weren’t for the racist murder, Green Lake wouldn’t have dried up. If it hasn’t dried up, Trout Walker (the worst character) would still have a source of income. If he still had a source of income, he wouldn’t be driven to poverty like what happened to him. But none of that would be a big deal had he not been so greedy. Because of that, he abused his children and grandchildren, forcing them to dig every day until they have found the treasure. And had he not abused his grandchildren, one of them wouldn’t have opened the prison camp Stanley spent most of the story in.
I also liked how in the book, those who engaged in an act of racism couldn’t get away with it, even during a time they would normally get away with it. Trout’s punishment, he lost all his fortune, died without finding the treasure, and once the treasure was found, he died in vain. Everyone else, the town has dried up, and it hasn’t rained until Camp Green Lake was shut down and the staff got in trouble.