What are ways you could keep a character hydrated in the wilderness?
The best way to consume fluids is by drinking them. For most people, water and a salty snack is going to be fine.
If the person is ill, doing strenuous activity, or is out in the hot sun, they may need ORS. You can make a really easy ORS solution by combining 1tsp Lite Salt (a salt product that is half sodium chloride and half potassium chloride) or 1/2 tsp regular table salt and a half cup of fruit juice to a liter of water. To either of those add 8 tsp of sugar (or lemonade powder). Taste it to make sure it is less salty than tears. Consume all at once or refrigerate any leftover portion and shake prior to giving.
If the person is unconscious and you can't give anything by mouth, you can give water slowly via an enema. The colon's job is to absorb fluid, and it can absorb up to 2 liters per day, as long as it's given slowly enough.
