Water Beneath the Water Beneath the SurfaceSurface

Chapter 6.3Chapter 6.3

Distribution of Water Distribution of Water UndergroundUnderground

Much of the water in soil seeps downward Much of the water in soil seeps downward until it reaches the zone of saturationuntil it reaches the zone of saturation

The The zone of saturationzone of saturation is the area where is the area where water fills all of the open spaces in water fills all of the open spaces in sediment and rocksediment and rock GroundwaterGroundwater is water below Earth’s surface is water below Earth’s surface

within the zone of saturationwithin the zone of saturation The The water tablewater table is the upper level of the is the upper level of the

saturation zone of groundwatersaturation zone of groundwater The The zone of aerationzone of aeration is the area above is the area above

the water table where the soil, sediment, the water table where the soil, sediment, and rock are not saturated with waterand rock are not saturated with water

Movement of Water Movement of Water UndergroundUnderground

Groundwater moves by twisting and turning Groundwater moves by twisting and turning through interconnected small openings through interconnected small openings

The groundwater moves more slowly when The groundwater moves more slowly when the the pore spaces are smaller pore spaces are smaller

PorosityPorosity is the percentage of pore spaces in is the percentage of pore spaces in rockrock Determines how much groundwater can be storedDetermines how much groundwater can be stored

Permeability Permeability is the ability to transmit water is the ability to transmit water through connected pore spaces through connected pore spaces AquifersAquifers are permeable rock layers or sediments are permeable rock layers or sediments

that transmit groundwater freelythat transmit groundwater freely

Features Associated with Features Associated with Subsurface Water – Subsurface Water – page page

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Water Beneath the Water Beneath the SurfaceSurface

AA springspring forms whenever the water forms whenever the water table intersects the ground surfacetable intersects the ground surface

Hot SpringsHot Springs have water that is 6–9ºC have water that is 6–9ºC warmer than the mean air temperaturewarmer than the mean air temperature Water is heated by cooling of igneous rockWater is heated by cooling of igneous rock

GeysersGeysers are hot springs that ejects are hot springs that ejects waterwater Water turns to steam and eruptsWater turns to steam and erupts

Geyser Eruption CycleGeyser Eruption Cycle

Water Beneath the Water Beneath the SurfaceSurface

A A wellwell is a hole bored into is a hole bored into the zone of saturationthe zone of saturation An An artesian wellartesian well is any formation is any formation

in which groundwater rises on its in which groundwater rises on its own under pressureown under pressure

Pumping can cause a lowering of Pumping can cause a lowering of the water tablethe water table

Pumping can form a cone of Pumping can form a cone of depression in the water tabledepression in the water table

Cone of DepressionCone of Depression

Environmental ProblemsEnvironmental Problems

Groundwater is being threatened Groundwater is being threatened by by overuseoveruse and and contaminationcontamination In some regions, the amount of water

available to recharge an aquifer is less than the amount being withdrawn

Common sources of groundwater pollution are sewage from septic tanks, farm wastes, and inadequate or broken sewers

CavernsCaverns A A caverncavern is a naturally formed is a naturally formed

underground chamberunderground chamber Erosion forms most caverns at or Erosion forms most caverns at or

below the water table in the zone below the water table in the zone of saturationof saturation

TravertineTravertine (sedimentary rock) is a (sedimentary rock) is a form of limestone that is deposited form of limestone that is deposited by hot springs or as a cave depositby hot springs or as a cave deposit Also known as dripstoneAlso known as dripstone

Cavern CharacteristicsCavern Characteristics

Formed from calcite deposited Formed from calcite deposited as dripping water evaporatesas dripping water evaporates

Formed in the zone of aerationFormed in the zone of aeration Common features include Common features include

stalactitesstalactites (hanging from the (hanging from the ceiling) and ceiling) and stalagmitesstalagmites (growing upward from the (growing upward from the ground)ground)

Karst TopographyKarst Topography

Formed by dissolving rock at, or Formed by dissolving rock at, or near, Earth’s surfacenear, Earth’s surface

Common features includeCommon features include SinkholesSinkholes are surface depressions are surface depressions

Sinkholes form when bedrock dissolves Sinkholes form when bedrock dissolves and caverns collapseand caverns collapse

Caves and cavernsCaves and caverns

Area lacks good surface Area lacks good surface drainagedrainage

Sinkhole FormedSinkhole Formed