Water Water

The World’s WaterThe World’s Water

Approx. 97% of the Earth’s water is salt waterApprox. 97% of the Earth’s water is salt water Approx. 3% is fresh water. Approx. 3% is fresh water.

– Of this 3%, most is frozen in the ice caps and in Of this 3%, most is frozen in the ice caps and in glaciersglaciers

– This leaves only about ½% of all Earth’s water This leaves only about ½% of all Earth’s water as usable fresh wateras usable fresh water

Most of this usable fresh water is found Most of this usable fresh water is found undergroundunderground

All of the Earth’s water is part of theAll of the Earth’s water is part of the hydrospherehydrosphere

Water CycleWater Cycle Movement of water from one part of the hydrosphere Movement of water from one part of the hydrosphere

to another is called theto another is called the water cyclewater cycle The energy to start the water cycle comes from the The energy to start the water cycle comes from the

sun (causes evaporation to begin)sun (causes evaporation to begin) Water enters the air as vapor from evaporation and Water enters the air as vapor from evaporation and

transpiration (water given off by plants)transpiration (water given off by plants) The vapor forms clouds, precipitation occurs, and The vapor forms clouds, precipitation occurs, and

the water flows back into the ground or into other the water flows back into the ground or into other bodies of waterbodies of water

The cycle then begins again – this is a continuous The cycle then begins again – this is a continuous cyclecycle

Where does rain go?Where does rain go?

EvaporatesEvaporates before it hits the ground.before it hits the ground.

Run offRun off ---if ground is impermeable or slope ---if ground is impermeable or slope is steepis steep

InfiltrateInfiltrate – moves into the ground ( if ground – moves into the ground ( if ground is porous and permeable)is porous and permeable)

Water in the GroundWater in the Ground characteristicscharacteristics

POROSITYPOROSITYThe percentage of open space in The percentage of open space in

the soilthe soil (The amount of water that the (The amount of water that the ground can hold depends on the ground can hold depends on the

amount of open space (pore amount of open space (pore space) between the soil space) between the soil

particles)particles)

The porosity of the soil depends on:The porosity of the soil depends on:

Particle shapeParticle shape– Rounded particles do not Rounded particles do not

fit together well, so they fit together well, so they will have more space will have more space between them between them

– Angular pieces fit Angular pieces fit together (like a puzzle), together (like a puzzle), and therefore will have and therefore will have less space between themless space between them

Rounded Rounded fragmentsfragments

Angular Angular FragmentsFragments

The porosity of the soil depends on:The porosity of the soil depends on:

• SortingSortingWell-sorted particles (all the same Well-sorted particles (all the same

size), don’t fit together well and have size), don’t fit together well and have the greatest pore spacethe greatest pore space

Unsorted particles have small Unsorted particles have small particles which fit between large particles which fit between large particles, decreasing the amount of particles, decreasing the amount of open spaceopen space

PackingPacking

Particles that compacted together will have Particles that compacted together will have less open space between them.less open space between them.

**Particle size does not affect **Particle size does not affect the porosity**the porosity**

Large particles have large spaces, but few Large particles have large spaces, but few of them. Small particles have small spaces, of them. Small particles have small spaces,

but many of them. The porosities will be but many of them. The porosities will be equal!!equal!!

PermeabilityPermeability

the ability of a the ability of a liquid to pass liquid to pass

through a through a material’s pore material’s pore

spacespace

Usually Usually permeabilitypermeability will increase as will increase as the size of the particles increasesthe size of the particles increases

The larger the particles, the larger the The larger the particles, the larger the pore spacespore spaces

Liquids (water) move easier through Liquids (water) move easier through larger openingslarger openings– (water moves easier through a fire (water moves easier through a fire

hose than through a garden hose)hose than through a garden hose)

gravel sand clay

ImpermeabilityImpermeability

If a If a liquid cannot pass liquid cannot pass through a materialthrough a material, , then it is considered to then it is considered to be be impermeableimpermeable

If a material is porous If a material is porous but the pores are not but the pores are not connected, then the connected, then the material will be material will be impermeableimpermeable

Soil Water MovementSoil Water Movement

When water When water infiltratesinfiltrates (soaks) into soil, (soaks) into soil, it gets pulled through the pores by it gets pulled through the pores by gravitygravity

The water continues to flow downward The water continues to flow downward until it reaches an until it reaches an impermeable layerimpermeable layer

The water then begins to fill in the pore The water then begins to fill in the pore spaces above the impermeable layer spaces above the impermeable layer – (like filling a glass with soda – the (like filling a glass with soda – the

soda hits the bottom of the glass and soda hits the bottom of the glass and then begins to fill the glass)then begins to fill the glass)

zone of saturation zone of saturation The layer of The layer of soil where all of the pore spaces soil where all of the pore spaces are filled is called theare filled is called the

water table – water table – top of saturated top of saturated zonezone

zone of aerationzone of aeration (air fills the pore (air fills the pore spaces) above the water table spaces) above the water table

capillary fringecapillary fringe– This is where tiny droplets of This is where tiny droplets of

water move upward by water move upward by attaching to small particles of attaching to small particles of soilsoil

CapillarityCapillarity

Ability of water to move upward Ability of water to move upward Capillarity is greatest when pore spaces Capillarity is greatest when pore spaces

are small.are small.

The Water TableThe Water Table

The depth of the water table variesThe depth of the water table varies, depending , depending upon the amount of rainfall, seasons, climate, soil upon the amount of rainfall, seasons, climate, soil thickness, etc.thickness, etc.

Where Where the water table does not reach the surface, the water table does not reach the surface, a pipe may be drilled into the ground down to the a pipe may be drilled into the ground down to the water table. water table.

Water may then be pumped out (similar to using a Water may then be pumped out (similar to using a straw to drink with) through the pipe. straw to drink with) through the pipe. – This is called an ordinary This is called an ordinary wellwell. . – If the water flows out of the pipe without being If the water flows out of the pipe without being

pumped, because of the pressure in the ground, pumped, because of the pressure in the ground, it is called an it is called an artesian wellartesian well..

Groundwater below a layer of solid rock or clay is in a Groundwater below a layer of solid rock or clay is in a confined aquifer.confined aquifer. The rock or clay is called a The rock or clay is called a confining layerconfining layer. A well that goes through a . A well that goes through a

confining layer is known as an confining layer is known as an artesian wellartesian well..

Groundwater usually remains cool all year. Groundwater usually remains cool all year. Because of its depth, groundwater is not Because of its depth, groundwater is not affected by the weather changes at the affected by the weather changes at the surfacesurface

Below 20 meters deep, water may become Below 20 meters deep, water may become heated by the Earth’s interior. heated by the Earth’s interior.

If it becomes heated to boiling, hot springs If it becomes heated to boiling, hot springs may rise to the surface. may rise to the surface.

They may also erupt as gushing springs of They may also erupt as gushing springs of boiling water and steam called boiling water and steam called geysersgeysers – (Yellowstone National Park in Wyoming is (Yellowstone National Park in Wyoming is

famous for its hot springs and geysers)famous for its hot springs and geysers)

Groundwater can Groundwater can dissolve limestone dissolve limestone underground. underground.

Carbonic acid naturally Carbonic acid naturally found in groundwater found in groundwater dissolves the calcite in dissolves the calcite in limestone. limestone.

Eventually, large portions Eventually, large portions of the limestone are of the limestone are dissolved and a cavern dissolved and a cavern (cave) may form. (cave) may form. – Howe Caverns in Howe Caverns in

upstate New York is an upstate New York is an example of a example of a limestone cavern.limestone cavern.

Groundwater ContaminationGroundwater Contamination

Groundwater can become polluted Groundwater can become polluted by many different meansby many different means

SinkholesSinkholes

Devil’sDevil’s Sinkhole, Sinkhole, Rocksprings, TexasRocksprings, Texas