Water Systems

We know from the water cycle that when precipitation falls, it will eventually end up back in the ocean... ... either from our sewer lines, or from rivers and streams.

But did you know that precipitation from Montana can flow all the way to Louisiana?

Actually, the water from nearly half the U.S. flows to Louisiana!

That’s because they are all part of the same watershed! A watershed is all the area that drains out the same river to get to the ocean. watershed

Watersheds are separated by a divide-- mountains that cause the water to flow to one side or another. divide

The water flows down small creeks and streams called tributaries... That later join the larger, main river! (the largest river system in the U.S. is the Mississippi!)

Of course we know that not all the water from an area goes downstream... Some of it stays trapped in lakes or ponds...

And some of it seeps underground! (This is called groundwater) groundwater

The dirt and small rocks have small holes called pores in them, which make them permeable. permeable layers This means water can pass through!

When there are no more cracks or pores for the water to pass through, it has reached an impermeable layer. impermeable layer This means the water can’t go through!

The water starts to collect into an underground pool called an aquifer. aquifer People used to believe they could find aquifers using dowsing or divining rods!

The layer that is full of water is called saturated. It can hold no more water! saturated The layers that can still absorb more water are unsaturated. unsaturated

When the unsaturated layers begin to get saturated, the water level begins to rise. water table This level is called the water table. water table

When the water table rises to above the ground, the result is a flood!

If the water table is not high, we have to dig a deep well to get to the aquifer.

But sometimes the water will come out on its own because of built up pressure. This can form a spring or artesian well!

And that’s all you need to know about our world of water! (for now....)