freshwater

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

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

A. EarthA. Earth’’s Waters Water

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

Water (or Hydrologic) CycleWater (or Hydrologic) Cycle

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

– It can: It can: InfiltrateInfiltrate the Earth the Earth’’s surfaces 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 Earth is a The Earth is a CLOSED CLOSED

systemsystem..

• Our water is limited and Our water is limited and must be must be conservedconserved

• Water is a sustainable and renewable resource

InfiltrationInfiltration – Seeping and absorption – Seeping and absorption of water into the ground surface as the of water into the ground surface as the result of percolation and storage. result of percolation and storage.

The Water CycleThe Water Cycle5. Ground Water5. Ground Water – Water that is found under – Water that is found under the Earththe Earth’’s surface as the result of s surface as the result of infiltration and storageinfiltration and storage

WATER BENEATH THE WATER BENEATH THE SURFACESURFACE

• Underground water provides drinking Underground water provides drinking water for more than 50% of the US water for more than 50% of the US population, 40% of irrigation water and population, 40% of irrigation water and more than 25% of industrymore than 25% of industry’’s needs.s needs.

• The amount of water underground The amount of water underground depends on:depends on:– Steepness of slopeSteepness of slope– Nature of surface materialsNature of surface materials– Intensity of rainfallIntensity of rainfall– Type and amount of vegetationType and amount of vegetation

• 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 Earthinfiltrate the Earth’’s s surface and surface and become part of the become 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

• AquifersAquifers: Permeable rock layers : Permeable rock layers that allow groundwater to move that allow groundwater to move freely.freely.

• AquitardAquitard: Impermeable layers that : Impermeable layers that do not let water pass through.do not let water pass through.

Water Beneath the SurfaceWater Beneath the Surface

• An An artesian well artesian well is any formation in is any formation in which groundwater rises on its own which groundwater rises on its own under under pressurepressure..– Conditions:Conditions:

•AquiferAquifer that is tilted and exposed to that is tilted and exposed to the surfacethe surface

•Aquitards both above and below the Aquitards both above and below the aquifer (which increases aquifer (which increases pressurepressure))


http://img.geocaching.com/cache/log/154e0f0f-6b9f-4e49-be90-dd1c6974f8ab.jpg

• Aquitards can block upward Aquitards can block upward movement of water causing it to movement of water causing it to move sideways. When the water in move sideways. When the water in the water table approaches the the water table approaches the ground surface, a ground surface, a springspring is formed.is formed.

• SpringSpring: Flow of water that emerges : Flow of water that emerges naturally at the surface.naturally at the surface.


• Hot springsHot springs: Groundwater is heated : Groundwater is heated at great depths and then quickly at great depths and then quickly flows to the surface (there are more flows to the surface (there are more than 1000 in the US).than 1000 in the US).

• GeyserGeyser: A hot spring/fountain that : A hot spring/fountain that shoots up with great force at shoots up with great force at intervals.intervals.


http://www.usgs.gov/newsroom/images/2008-5-30/old_faithful_hires.jpg


• 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


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

particle size the particle size the better the capillaritybetter the capillarity

• Formations associated with Groundwater:Formations associated with Groundwater:– CavernsCaverns: Naturally formed underground chambers.: Naturally formed underground chambers.

•Most are formed by water erosion with limestone Most are formed by water erosion with limestone at or below the water table in the zone of at or below the water table in the zone of saturation.saturation.

•Dripstone features (dripping water leaves behind Dripstone features (dripping water leaves behind minerals):minerals):

– StalactitesStalactites: Hang from the ceiling.: Hang from the ceiling.– StalagmitesStalagmites: Build up from the floor.: Build up from the floor.– May join together to form a May join together to form a columncolumn..

6.3: Water Beneath the 6.3: Water Beneath the SurfaceSurface

freshwater

Education

ground water water

ground water ground

water table

earths water

underground water

porosity water

water pass

liquid water