Download Water Underground

Water Underground
Coulter
How water moves underground…
 Water underground trickles down between particles of soil and through
cracks and spaces in layers of rock.
 Different types of rock and soil have different-sized spaces (pores) between
their particles.
 The size of pores determines how easily water moves through rock and soil.
 Permeable: characteristic of a material that is full of tiny, connected air
spaces that water can seep through.
How water moves underground…
 As water soaks down through permeable rock and soil, it eventually
reaches layers of material that it cannot pass through.
 Clay and granite are impermeable, meaning that water cannot pass
through easily.
Water zones
 Once water reaches an impermeable layer, it is trapped. The water begins
to fill up the spaces above the impermeable material.
 The area of permeable rock or soil that is totally filled, or saturated, with
water is called the saturated zone.
 The top of the saturated zone is the water table.
 The layer of rock and soil above the water table is called the unsaturated
zone.
Bringing up Groundwater
 Springs can form as groundwater
bubbles or flows out of cracks in
the rock.
 Aquifer: any underground layer of
rock or sediment that holds water.
 Aquifers can range in size from
small underground patch of
permeable material to an area
the size of several states.
Wells
 The depth of a water table can vary greatly over a small area. Generally,
the level of a water table follows the shape of underground rock layers.
 People can obtain groundwater from an aquifer by drilling a well below the
water table.
Subsidence
 Subsidence–ground surface settlement due to the consolidation or
collapse of the underlying geologic material