Coulter Water underground

How water moves underground Water underground trickles down between particles of soil and through cracks and spaces in layers of rock. Different size particles have different sized spaces between them.

Effects of different materials Size of pores (space between) determines how easily water moves through rock and soil. If the pores are connected, this too affects water movement. Because they have large and connected pores, materials such as sand/gravel allow water to pass through, or Permeate They are known as PERMEABLE materials

Effects of different materials Eventually water reaches a layer of material that it cannot pass through. These have few or no pores (clay and granite). Clay and granite are impermeable, meaning water cannot pass through easily.

Water zones Saturated zone- layer of permeable rock or soil in which the cracks and pores are totally filled with water. Water table- the top of the saturated zone. Unsaturated zone- soil and rock layers above the water table contain some moisture, but the pores contain air and water, they are not saturated

Bringing up groundwater Springs can form as groundwater bubbles or flows out of cracks in the rock. Aquifers- underground layer of rock or sediment that holds water. Aquifer can range in size from small underground patch of permeable material to an area the size of several states.

aquifers The rate of movement of underground water depends on the slope of the aquifer and the permeability of the rocks. Ground water may stay in an aquifer for thousands of years before reaching the surface again.

Wells People obtain groundwater from an aquifer by drilling a well below the water table.