Groundwater Water that soaks into the ground as it enters tiny air spaces in the soil and rocks.

Groundwater Recharge area – region that permits water to flow down due to gravity Zone of saturation – an area where all the spaces are filled with water. It’s top is called the water table

Groundwater A water table’s depth depends on where you are. At the beach, the water table is close to the surface because you are at sea level. In the desert, the water table may be very deep in the ground. What happens when the water table is above the surface?

Water table The level of the water table can be affected by different factors. These can include: Amount of rainfall Amount of time between rains Season Slope of the ground Climate humans

Groundwater Zone of aeration – An area of ground that holds some water and has air filled pore spaces, located between the water table and the surface

Groundwater Directly above the water table is the zone of aeration. Made of layers – one layer in particular is the capillary fringe. This is where water rises because it is attracted to the soil. This is called capillary action.

Porosity Amount of water that soil and rock can hold depends on its porosity. Porosity – the percent of a material’s volume that is pore space.

Porosity Porosity = Volume of pores x 100 total volume A rock that is porous can hold a lot of water but may not let water pass through ex: cork, pumice

Permeability Permeability – ability of rock to allow water to pass through depends on the extent to which pores are connected to each other and the size of the pores Examples – sand, gravel –permeable - silt – less permeable - clay and shale - impermeable

Groundwater Deep in bedrock of Earth are layers of rock made of dense materials (granite, clay) or areas that are not easily penetrated by water. Layers are called aquitards or aquicludes. Confining layers that stop or slow the vertical movement of water.

Groundwater When water reaches an aquitard or aquiclude, the water pools under the surface and flows in a horizontal direction towards a body of water on the surface (lake, river) Aquifers – layers through which groundwater flows

Aquifers a geologic formation that stores and/or transports water Unconfined aquifer has permeable layer above Confined aquifer has impermeable layers both above and below it; may also be under pressure

An aquifer’s recharge area may be far away.

Contamination of aquifers occurs from the surface Contamination of aquifers occurs from the surface. Since groundwater moves slowly, contamination continues for many, many years.

Ordinary wells and springs Ordinary well – a well that is made by humans digging or driving into the ground Spring – on a hillside where the water table meets the surface

Artesian wells Wells that create enough pressure when put into the ground to force water to the surface without pumps.

Cone of depression Created when groundwater is pumped from a well. Instead of moving toward a body of water, the groundwater flows toward the well from every direction. The pumping well creates an artificial area of release by drawing down (lowering) the water table around the well.

Geysers A hot spring that shoots columns of hot water and steam into the air. How does it work? Consist of very long, irregular shaped tubes. When tube is full, water at the bottom has so much pressure that its temperature surpasses its boiling point but cannot evaporate. Eventually some water towards the top boils and begins to flow out. When the pressure is released, the superheated water boils instantly and the steam rises and pushes out (taking water with it) Old faithful