Where does groundwater come from? Can you say, ‘Hydrologic Cycle?’

This USGS diagram shows the Hydrologic Cycle. If you want to know where the groundwater in McHenry comes from,
look here.

Where does groundwater come from? The obvious answer is ‘from the ground.’ But, where does the ground get it? That well out behind your Bull Valley home extends down into the ground and pumps groundwater up so you and your family can use it. It would be nice to know where the groundwater comes from, wouldn’t it?

The first thing to know is that the groundwater is there as part of the hydrologic cycle. Assuming you haven’t remembered all the particulars from your 5th-grade lesson, that cycle works like this:

THE HYDROLOGIC CYCLE

1. Evaporation: the water in lakes, rivers, oceans and on the surface of the ground is evaporated into the air …
2. Where it condenses to form clouds.
3. While trapped in the clouds, it moves with the wind.
4. Then, the moisture returns to the earth in the form of precipitation: rain, sleet, snow
5. A portion of the water runs off back into lakes, rivers, and oceans – another portion seeps into the ground. Through gravity, much of this water goes lower and lower until it reaches an area that is resting on an impervious surface.
6. When that area is saturated, your well has the ability to gather portions of the water and pump them back to the surface and through the pipes into your home.

Keep in mind that water can also move in the ground through aquifers. Governments have come to recognize the importance of aquifers. You can even look up a map of aquifers in the area called the “McHenry County Sensitive Aquifer Recharge Areas.”

This map shows areas in two shades of green where aquifers are considered sensitive. On that map, you’ll find that much of Bull Valley is covered by dark green – the most sensitive areas of the map.

This means that groundwater is moving under your feet. Your well’s job is to catch portions of the groundwater and pump them up into your Bull Valley home.