WATER BENEATH THE SURFACE

Last week… 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.

Vocabulary

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 Infiltration is the process of water

entering the soil. Since water has infiltrated (entered) the

soil, it is considered groundwater.

Porosity & PermeabilityPOROSITY PERMEABILITY

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.

Porosity

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

Permeability

Which picture shows the most permeability?

Which picture shows the least permeability?

Aquifers An underground body of rock or sediment

where large amounts of water can flow and be stored is called an aquifer.

Groundwater Diagram

Wells and Springs

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

Wells and springs are divided into two groups – Ordinary

- Artesian

Ordinary

ORDINARY WELL ORDINARY 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

ARTESIAN WELL ARTESIAN SPRING

A manmade hole where water flows freely without being pumped

Water flowing through cracks in impermeable rock