 Last week we discussed how run-off can occur two different ways:  Surface Run-off – water flowing on the surface to streams, rivers and oceans.  Subsurface Run-off – water absorbed by and flowing under the ground. It still flows back to oceans.

 Aeration Zone – the zone that lies between the water table and the Earth’s surface  Saturation Zone – The layer of an aquifer where the pore space is completely filled with water.  Water Table – the boundary line of the zone of saturation.

 Infiltration is the process of water entering the soil.  Since water has infiltrated (entered) the soil, it is considered groundwater.

POROSITYPERMEABILITY  Groundwater seeps down through the soil and fills the pores, or spaces between rock particles.  Porosity is the indicator of how much groundwater those pores can store.  Sometimes the pores in the ground are connected to each other.  Permeability is the ease that water can pass through a porous material.  A substance is impermeable if water cannot flow through it.

 Which picture shows greater porosity?  Which picture shows lesser porosity?

 Which picture shows the most permeability?  Which picture shows the least permeability?

 An underground body of rock or sediment where large amounts of water can flow and be stored is called an aquifer.

Wells and Springs

 A WELL is a manmade hole dug in order to access groundwater.  It is manmade, so it is not natural.  A SPRING is a place where the water table naturally meets the ground’s surface.  It is a natural flowing of water from a natural hole in the ground.

 Wells and springs are divided into two groups – Ordinary - Artesian

ORDINARY WELLORDINARY SPRING  An ordinary well is a hole that is dug below the water table to bring groundwater to the surface  An ordinary spring is a natural flowing of groundwater out onto the surface

ARTESIAN WELLARTESIAN SPRING  A manmade hole where water flows freely without being pumped  Water flowing through cracks in impermeable rock