Symbolism, Imagery, Allegory
The landscape in and around Camp Green Lake is practically another character in Holes. Throughout the book, the natural world seems to respond to the emotional and moral lives of the characters, developing right along with them. For instance, the ground the campers dig in is hard and barren, just like the campers' lives. And as Stanley and Zero move farther away from the camp and closer to their fateful trip up the mountain, the landscape around them becomes much more welcoming.
Louis Sachar can be a subtle writer, but there's one time when we're just hit over the head with the symbolic nature of, um, nature. We're thinking about the lack of rain that destroys the town of Green Lake and shrivels up Trout Walker's fortune. The rain stopped right after Sam's murder, and the drought seems to be a punishment for the immoral people who lived there. But once Green Lake is redeemed (by Stanley and Zero), the rain falls again. And you know what that means: a new beginning not only for the characters, but for the land itself.