The water cycle

Unit 7: Water Cycle & Unit 7: Water Cycle & ClimateClimate

• No other planet in the solar system has the No other planet in the solar system has the unique combination of fluids which Earth unique combination of fluids which Earth does. Earth has a surface that is mostly does. Earth has a surface that is mostly covered with liquid water, water vapor in the covered with liquid water, water vapor in the atmosphere, and both frozen and liquid atmosphere, and both frozen and liquid water on the land.water on the land.

A. Earth’s WaterA. Earth’s Water

• The The continuous interchange of watercontinuous interchange of water between the atmosphere and Earth’s between the atmosphere and Earth’s surface.surface.

• Includes the phase changes of water Includes the phase changes of water and and the movements of water above, the movements of water above, on, and below the Earth’s surface.on, and below the Earth’s surface.

Water (or Hydrologic) CycleWater (or Hydrologic) Cycle

• PrecipitationPrecipitation: The falling of water as : The falling of water as liquid (rain) or solid (ice, hail, and snow).liquid (rain) or solid (ice, hail, and snow).

– It can: It can: InfiltrateInfiltrate the Earth’s surface the Earth’s surface RunoffRunoff from the surface into streams, lakes or from the surface into streams, lakes or

oceanocean Be storedBe stored in the form of ice and snow in the form of ice and snow Be Be evapotranspiredevapotranspired back into the atmosphere back into the atmosphere

from large bodies of water, soil, plants and animalsfrom large bodies of water, soil, plants and animals

Infiltration

http://www.enchantedlearning.com/label/

The Water CycleThe Water Cycle• Ground WaterGround Water – Water that is found under – Water that is found under

the Earth’s surface as the result of the Earth’s surface as the result of infiltration and storageinfiltration and storage

• How does water How does water infiltrate the infiltrate the ground?ground?

– Before runoff and Before runoff and evapotranspiration, evapotranspiration, water will usually water will usually infiltrate the Earth’s infiltrate the Earth’s surface and become surface and become part of the part of the groundwatergroundwater..

Ground WaterGround Water

1.1. In order for water In order for water to move into the to move into the surface materials surface materials of the Earth, the of the Earth, the materials materials (rocks/soil) must (rocks/soil) must be be permeable permeable and and unsaturatedunsaturated..


2. 2. PorosityPorosity – – The ratio of the volume of openings compared to the volume of the material..

• Depends on: Depends on: Shape Shape of the particles Looseness Looseness of the particles. How well sorted sorted the material isthe material is

PorosityPorosity

• Water will pass Water will pass more easily more easily throughthrough a cylinder a cylinder full of round beads, full of round beads, than a cylinder full than a cylinder full of square blocks of of square blocks of the same size.the same size.

PorosityPorosity


3. PermeabilityPermeability – A – A material is said to be material is said to be permeable if it allows permeable if it allows water to pass through water to pass through the connecting pore the connecting pore spaces of the material.spaces of the material.

• How permeable a How permeable a material is depends on material is depends on the the porosityporosity


• The The larger the pore spaceslarger the pore spaces between between the particles that make up a the particles that make up a material, the material, the greater the greater the permeabilitypermeability of that material. of that material.

– Gravel (large) = Gravel (large) = High permeabilityHigh permeability– Clay (very small) = Clay (very small) = Low permeabilityLow permeability

•Precipitation recharges the groundwater supply. •Wetlands and streams are present where the water table lies at the ground surface. •Streams gain water during the wet season and may lose water during the dry season.

Groundwater flows down the hydraulic gradient (slope) from high elevations to low elevations. The shape of the flow path varies depending upon the local geological characteristics.


• Zone of AerationZone of Aeration – Portion of ground through – Portion of ground through which water passes until the water reaches the which water passes until the water reaches the zone of saturation.zone of saturation.

• Zone of SaturationZone of Saturation – Portion of saturated – Portion of saturated ground with an upper boundary called the water ground with an upper boundary called the water table.table.

• Water TableWater Table – The top of the zone of saturation – The top of the zone of saturation



• Ground Water can be easily Ground Water can be easily contaminated by:contaminated by:

• LandfillsLandfills• HerbicidesHerbicides• FertilizersFertilizers• Underground Storage Tanks (gasoline)Underground Storage Tanks (gasoline)• OilsOils• Failed Septic SystemsFailed Septic Systems


4. CapillarityCapillarity – – upward movement upward movement of water against the of water against the force of gravity in a force of gravity in a narrow space, such narrow space, such as a tube, plant as a tube, plant vessel, or fine sand vessel, or fine sand particles.particles.• The smaller the The smaller the

particle size the particle size the better the capillaritybetter the capillarity

C. Surface Water & RunoffC. Surface Water & Runoff

• Surface Water – Surface Water – Water which does not Water which does not infiltrate or evaporate (ponds, streams, infiltrate or evaporate (ponds, streams, lakes, etc)lakes, etc)

• Runoff – Runoff – When water moves over the When water moves over the surface of the Earthsurface of the Earth..– Occurs when rainfall exceeds Occurs when rainfall exceeds

permeability rate or slope of the surface permeability rate or slope of the surface is too steep to allow infiltration to is too steep to allow infiltration to occur.occur.

Climate Climate [9 min][9 min]

ClimateClimate

1.1. Climate Climate is the is the average average temperature and temperature and moisture conditions moisture conditions over a long period over a long period of time.of time.

• Water BudgetWater Budget – a – a system of system of accounting for accounting for moisture income, moisture income, storage, and outgo storage, and outgo for the soil in a for the soil in a specific area.specific area.

A. Water BudgetA. Water Budget

1.1. Potential Evapotranspiration (PEPotential Evapotranspiration (PE): ): All All the water that could enter the air from the water that could enter the air from plants and evaporation.plants and evaporation.

2.2. Precipitation (P)Precipitation (P): : All moisture from the All moisture from the atmosphere; rain, snow, hail and sleet.atmosphere; rain, snow, hail and sleet.

– StorageStorage: : Amount of water stored in soil, Amount of water stored in soil, snow & surface water.snow & surface water.

– UsageUsage: : water evaporated or used = storage water evaporated or used = storage decreases.decreases.

– Recharge: Recharge: Precipitation.Precipitation.

3.3. SurplusSurplus: Water above what is lost naturally : Water above what is lost naturally from the soil (when P is greater than PE)from the soil (when P is greater than PE)

4.4. Humid climatesHumid climates are those in which the total are those in which the total amount of P is greater than the total amount of amount of P is greater than the total amount of PEPE

5.5. Deficit Deficit : Water that would be lost above what is : Water that would be lost above what is in the soil if it were present (when P is less than in the soil if it were present (when P is less than PE) PE)

6.6. Arid climatesArid climates have significantly more total PE have significantly more total PE than Pthan P

2. Climate Pattern Factors2. Climate Pattern Factors

a.a. LatitudeLatitude• Most important Most important

factor in factor in determining determining climate, especially climate, especially temperatures temperatures

• Controlled by Controlled by INcoming SOLAr INcoming SOLAr radiaTION radiaTION (Insolation)(Insolation)

•As latitude increases, yearly temperature range (difference between highest and lowest temperature) increases.

b.b. ElevationElevation• As As

elevation elevation increasesincreases, average , average yearly yearly temperatutemperature re decreasedecreasess..

c.c. Large Bodies of Water – Large Bodies of Water – moderate coastal climates because moderate coastal climates because water keeps heat longer!water keeps heat longer!

MarineMarine ContinentalLocation: Ocean/large lakeOcean/large lake Interior (land)Interior (land)Winds from: OCEANOCEAN LANDLANDSummers: Cooler than Cooler than

Average (Mild)Average (Mild)Warmer than Warmer than average (HOT)average (HOT)

Winters: Warmer than Warmer than Ave. (Mild)Ave. (Mild)

Colder than Colder than Ave.Ave.

(Harsh)(Harsh)Example: San Francisco, San Francisco,

LA, DCLA, DCKansas, NE, IA, Kansas, NE, IA, SyracuseSyracuse

Orographic Effect and Cloud Orographic Effect and Cloud FormationFormation

d.d. Orographic EffectOrographic Effect

– Orographic EffectOrographic Effect – Mountains act as – Mountains act as barriers to prevailing winds. As the wind barriers to prevailing winds. As the wind hits the windward side of a mountain, hits the windward side of a mountain, the the air is forced up, cools, condenses and air is forced up, cools, condenses and forms clouds with precipitation.forms clouds with precipitation.

– Windward sideWindward side – Side of the mountain – Side of the mountain that is exposed to the wind. that is exposed to the wind. WETWET

– Leeward SideLeeward Side – Descending air warms – Descending air warms and it holds more moisture, making it and it holds more moisture, making it DRYDRY..

WINDWARD

LEEWARD

Prevailing Wind

Air R

ises

, Exp

ands

&

Cools

Air Sinks, Compresses & W

arms

*Why does rising air cool? *As air temperature decreases, its ability to hold water___________*Why does falling air warm?

Cascade Mountains

Condensation &

Precipitation

Now Answer the questions on page 12

e.e. Ocean CurrentsOcean Currents• The "Global Conveyer Belt" shows how the oceans The "Global Conveyer Belt" shows how the oceans

move energy from the tropics to the poles and back move energy from the tropics to the poles and back again in order to moderate Earth's climate. This is again in order to moderate Earth's climate. This is accomplished through long-term ocean circulation.accomplished through long-term ocean circulation.

•Interesting Interesting fact:fact: It takes It takes up to 1000 up to 1000 years for years for water to water to completely completely circulate the circulate the oceans!oceans!

1.1. Surface Currents – Surface Currents – like like huge “rivers” in the oceanhuge “rivers” in the ocean

– Can be found on page Can be found on page 44 of the ESRT of the ESRT

2.2. El NinoEl Nino• A A warm ocean currentwarm ocean current resulting from a resulting from a

reversal of the ocean current in the Pacific reversal of the ocean current in the Pacific which results in which results in climate variabilityclimate variability..

f.f. Wind BeltsWind Belts

– Uneven heating of the Earth produces Uneven heating of the Earth produces global wind belts and pressure belts. global wind belts and pressure belts. These “pressure belts” determine the These “pressure belts” determine the wetness or dryness of a particular wetness or dryness of a particular location. Low pressure occurs where air location. Low pressure occurs where air is rising and thus precipitation occurs. is rising and thus precipitation occurs. High pressure regions are areas that High pressure regions are areas that lack rainfall (DRY).lack rainfall (DRY).

You can find the planetary wind belt diagram on your ESRT page 14

Complete the worksheet on page 15 using

your ESRT! Due tomorrow!

Documents

The water cycle