Reason for so much water....it isnt just for drinking,think heat stroke.Getting overheated can kill you.

With water pour it over your shirt,soak your bandana,soak your hat,it will act as an evaporation cooler and when you are HOT it may save your life.Heat stroke,if you ever had it you know its not to be trifled with.

Even if you have to wait 4-6 hours for AAA to come get you,those gallons of water can be a life saver just in that short amt of time.