Danger on Midnight River: World of Adventure Series, Book 6

Slow-learner Daniel Martin escapes his peers' teasing by spending most of his time outdoors. But when a van crash plunges him and a gang of bullies in the river, Daniel must choose between saving himself and risking his life to save the others. The tables are turned when Daniel, always the joke, becomes the hero and the only one who can save his classmates from the perilious rapids of the rivers.