As with most movies involving sensitive subject, the viewer is left to choose sides. Fracking is a complex operation, but can be done safely and without environmental impact. It can also be done with safety concerns and be environmentally destructive. This movie leaves that undetermined, which is intentional as the decision to or not to frack is not the intent, rather a feeder to the moral content of the story. To that end, the storyline is fairly believable.
As Damon stated in the film, "Geography was never my strong suit", so they should have appointed a more knowledgeable person to find the tainted farm. Although parts of Louisiana are coastal, Lafayette is not near the coast, wouldn't suffer from a salty atmosphere, nor have any lighthouses.