system
Given the following post, respond as if you're commenting on Reddit:
human
What’s stopping the water in lakes from seeping into the soil and ‘disappearing’?

Thought about this question when I was watering some plants and the water got absorbed by the soil. What’s keeping a body of water (e.g. in a lake) from being absorbed by the soil completely?
gpt
Because there’s already water in the ground. If you were to dig down beside the lake you’d hit saturated dirt at the same level as the surface of the lake. The level at which this occurs is the “water table.” Water flows under ground and levels out so if you dig a hole and keep the hole open, it will fill with water up to the water table. We call those holes “wells.”  
  
Of course nature is more complicated than that simple model, but that’s basically it. Rivers can lose water to the surrounding ground as they flow or gain water. Perched aquifers above the surrounding water table can occur when there are pockets of impermeable material holding water like a bowl. Those impermeable layers are called “aquatards.” If there is a lot of rain in an area the ground above the water table can be permanently saturated, but the water is moving downward to the water table. Coasts are more complicated when tides are involved.