These are small holes in the ground that are, yup, filled with water. Often they started as a Monster-dug
Hidey-hole or
Pit that filled after heavy rains. The holes are good for providing the water necessary for survival. Each time you come across a Waterhole you will drink from it. Well, not every time - you have to be thirsty. If the water is cloudy, you'll have to be very thirsty. Sure, sickness can result from drinking bad water - some Waterholes might even be poisoned! (Who would do such a dastardly thing?) It is not so easy to judge how good the water is either.
