SEE NO EVIL HEAR NO EVIL - Where did Walley get those rubber boats

When David and Walley are pushing the police car out of the swamp from after the police chase. They both get into an argument and Walley says he can do this without Davids help and David starts walking away. Now watch when David is walking out of the swamp toward the train tracks. They show a shot of Walley saying "Well i'm going to need help to get out of here." At the time he's saying that you can see that he is wearing black knee high rubber boots. Where did he get those from?