Land is very important to the water cycle. A WATERSHED is any area of land that water flows across or through. Where is the water going? Downhill of course. Water in a watershed trickles and flows toward a common body of water, such as a stream, river, lake or coast. Watersheds can be big or small, but they usually have high points (like ridges) as their upper boundaries. So watersheds capture water, store it and eventually release it farther downhill.
What sort of land is your watershed made of? It's easy to find out. First you need to know if the land where you live is steep or flat.
- Steep land makes water run off in fast-moving creeks and rushing rivers.
- Flat land allows water to collect into lakes, ponds and swamps.
Now think about what happens when you dig a small hole. Do you find solid rock, fine silt or dirt that is loose and sandy?
- Loose ground (like gravel or sand) is POROUS, which means it has lots of little gaps that water can easily sink into. When water sinks into the ground, we call it GROUNDWATER, and it fills an underground water supply called an AQUIFER.
- Tightly packed ground, like clay or solid rock, isn't very porous at all, so it's hard for water to move through. Layers like that can trap water at the surface or below ground.