STRATIGRAPHY AND SEDIMENTATION (GROUNDWATER) Flashcards
most important and widely available freshwater resources
Ground water
this is the form of the largest volume of freshwater
Glacial Ice
this represents the largest reservoir of freshwater that is readily available to humans
Groundwater
How much of the liquid freshwater is made up of groundwater
96%
What are the Geologic Roles of Groundwater?
1) Erosional agent
2)Equalizer of Streamflow
Factors which affect dstribution of groundwater?
1) Steepness of Slope
2) Nature of surface material
3) Intensity of rainfall
4) Amount and type of vegetation
Is clay permeable?
No
A near surface zone wherein water soaks and does not travel far because it is being held by the molecuar attraction as a surface film on soil particles
Belt of soil Moisture
zone where all open space in sediments and rocks are completely fille with water
Zone of Saturation
Water situated within the Zone of Saturation
Groundwater
Upper limits of the zone of saturation
Water Table
Area above the water table where sediments and rocks are not saturated
Unsaturated Zone
Why is water in unsaturated zone not usable?
Because it clings too tightly to rock an soil particles
What is the usual shape of water table?
Replica of the surface
Factors contributing to the irregular surface of Gwater
1 Slow movement of G water which tends to pile up in high areas
2 Variations in rainfall
3 Earth surface permeability
Factors influencing the storage and movement of gwater
Porosity and permeability
What is porosity?
volume of voids over total volume of rocks
percentage of the total volume of sediments that consists of pore spaeces
countless voids or openng ins bedrick, soil and sediment
pore spaces
voids left by escaping gases from lava
vesicles
factor that determine amount of pore spaces
Size and shape of grains
packing
sorting
amount of cementing materials
what provides porosity or void in ign and met rocks?
Fractures
This is the ability of a rock, sediment or soil to transmitt fluid which depens on the connectedness of voids
Permability
What is the porosity and permeability of clay?
Highly porous but impermeable
Imepermeable layers that hinder or prevent water movement
Aquitard
What are the usual compositions of aquitard
Clay or fine grained
Permeable rock strat or sediments composed of larger particles such as sand and gravel which permits freely movement of groundwarer
Aquifer