All water in the ground

(occupying the pore space in bedrock and soil)

-3rd most abudnant reservoir on earth

-most of it from rainfall

-water everywhere beneth the land surface

(but decreases w/ depth after 750m)

-divided into 2 major zones

(unsaturated zone & saturated zone)

(zone of aeration)

-water may be present, dosnt mean it saturates into the ground

-soil and rock near the surface

-open spaces filled w/ mixture of air & water

boundary between

(unsaturated zone & upper sufrace saturated zone)

-always present

-Water moves toward low points (in topography) influned by gravity

(slopes toward streams or lakes)

-Balance b/w removal & addition of water can affect the water table

-most groundwater within few hundred meters of surface is in motion

(not like streams)

-groundwater velocites are slow

(cm-per day/ m-per year)

-groundwater move through small, constricted passages, along tortuous route

Portion of total volume of a (regolith or bedrock) that has open spaces that have gravels

Porosity of sedimentary rocks affected by

-partical size, shape, arrangement

-extent of cementation

Porosity of Igneous & Metamorphic rocks are generally low

Measure of how easy fluid can travel through a porous medium (solid)

-having low posiperty=low permeability

(not the same for high)

-pore amounts,sizes, how well they are connected is determind by permeability

Process by which underground is replenished

-an area where precipitation steeps downward beneth surface and reaches saturated zone

-without recharge, water tables fall

-great recharge water tables rise and intersect the surface

Process by which underground water reaches streams or lakes

-springs

-pumping wells

-artesian water

-if discharge exceeds recharge, water table fails

-body of rock that is highly permeable that can store water and yelid sufficient quanites to supply wells  & springs

(holds & transports water)

-sandstone

body of rock

-causes it slow down but does not hold back the flow  of water from the adjanent aquifer

(flow of water slow down)

body of relatively impermaeable rock adjacent to permeable one

-capable of absorbing water slowly

-does not transmit it rapidly enough to supply to well or spring

-aquifer bounded by aquicludes

-not overlain and confined by aquiclue

(aquifer that has the water table as its upper boundary)

Example

 -High Plains aquifer, which lies at shallow depths beneath the High Plains of the U.S

-30% of groundwater used for irrigation in U.S is obtained from High Plains aquifer

-Kansas,Mexico,& Texas, water table has dropped so much over half century that the thickness of the saturated zone has declined by than 50% 

Forms when groundwater moves through (limestone) and dissolves it away

-natural underground opening 

-connected to the surface

very large cave or system of interconnected cave chambers 

ex.

-Carlsbad, New Mexico=one chamber 1200 m long, 190 m wide, 100 m high

(formed from surface acid)

-Mammoth Cave, Kentucky=consists of interconnected caverns w/ aggregate length 48 km

(discharge)

-flow of groundwater emering naturally at ground surface

-occur whereever the land surface cuts down to the water table

-streams and lakes form this way

(discharge)

-supplies water only if intersecting with water table

-drilled below water table in permeable rocks

-pumping creates a cone of depression, causing water table to drop, unless water is added

(discharge)

-confined aquifer with water table upslope

-weight of overlying water forces water up & outward

-dry regions, withdrawal exceeds natural recharge

-Groundwater can be nonrenewable resource

(Over pumping & Contamination)

Fissures=take all water out (makes area fall apart)

Subsidence=makes ground move down

Depending on:

-how much water pressure is reduced

-thickness and compressibility of the aquifer

Sewage

Fertilizers

Toxic Chemicals

-metals

-organics

--solvents

--gasoline

--pesticides

-Dissolution (important carbonates & evaporites/rainfall)

-Cementation

-Replacement

- forms features overtime after limestone dissolves 

-a feature is forming caves

landscape where caves & sinkholes are so numerou forming a peculiar topography characterized by:

-many small, closed basins

-disrupted drainage patterns

-streams disappearing into ground

-streams reappearing as large strings

(extreme karsting leaves towers as remnants)