The River
by: Gary Paulsen

Two years ago Brian's accident left him stranded in the woods alone and amazingly he survived. (Read Hatchet) This time they want him to do it all again on purpose so they can learn survival skills from him.
Brian agrees, but the emergency supplies go back with the plane or Brian says he won't stay with Derek.  Derek is going to record the entire experience, and he agrees to send everything back except the radio.  Little did they know they would need those supplies and radios break.