How come bodies of water (lakes, rivers, wetlands, oceans even…) exist above ground instead of the water simply being absorbed by the earth?
In: 855
In detail it is actually a quite complicated question. But one of the most important parts is how the bodies of water above ground interact with groundwater below the ground. Groundwater is the water that fills spaces between grains in soil or rock or fills fractures or cavities in the rock.
Most rivers and lakes are directly connected to the groundwater. They can gain water from the groundwater or lose water to the groundwater. Or gain water in one place and lose water in another. But overall, most river and lake systems gain water from the groundwater. And where does the groundwater come from (aside from from rivers and lakes)? Precipitation on hills and uplands above the rivers seeps into the ground until it reaches the top of the saturated groundwater (called the water table). Then the groundwater slowly flows to rivers, lakes, or the ocean. This is enough to keep most rivers flowing between rainstorms and keeps lakes full of water.
Latest Answers