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23 Cards in this Set
- Front
- Back
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Fresh water compaired to Salt (saline water)
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Fresh 3.5%
Salt Water 96.5% |
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Why is fresh water important/what is it used for?
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Use for:
-irrigation -thermoelectric power -public and demestic use -industrial use -aqua culture -mining -livestock |
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Where is most freshwater located?
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ice caps and glaciers
ground water |
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Water Cycle (10)
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1) evaporation
2) air currents 3) condensation 4) precipitation (rain snow hail) 5) run off 6) inflitration 7) ground water flows 8) Groundwater flows onto surface 9) Transpiration from plants 10) Most precipitation into ocean; some evaporates on way down |
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infiltration
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water seeps into the ground
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Porosity
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Proportion of Open Space
-Rounded, sorted clasts do not fit tightly -Poorly sorted, angular clasts fit more tightly |
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Permeability
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Pores Connected So Fluids Flow, can water flow through?
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high permeability examples
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-Granite with many connected fractures
-Loosely cemented gravels |
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low permeability examples
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Compacted clay (shale)
Porous volcanic rock with separate pores |
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The best water-bearing body of rock or sediment (aquifer) would have the following properties:
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high porosity and high permeability
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Most groundwater is in ____________ between clasts
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pourus spaces
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location of pours and saturation
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Pores in upper parts generally unsaturated
Below water table pores saturated with groundwater |
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Watertable
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Top of saturated zone
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How Does Groundwater Accumulate? (6)
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1) Rain or snowmelt can evaporate or be captured by plants
2) can flow down the surface as runoff 3) can accumulate on the surface in wetlands and lakes 4) can seep into the ground 5) can reach the water table and seep down into the saturated zone 6) Below the water table, can flow if the rocks are have interconnected spaces |
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Groundwater in fractures
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-Fractures can contain groundwater
-May be the only pathways for water, if interconnected |
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Groundwater in Cavities
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-Some rocks, especially limestone, have cavities
-Cavities can contain groundwater - NOT where most occurs |
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Where does groundwater communicate directly with surface water
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in unconfied aquifers
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How Can Water Become Contaminated?
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Mining and naturally mineralized rock
landfill farm septic tank Leaking tank in gas station truck fuel spill Brought from outside area by groundwater householes drycleaners Fuel storage tanks factories |
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Confined vs Unconfined aquifer
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Confined- sealed top and bottom, don't communicate, overlain by less permeable materials
Unconfined- communicate with surface, pen to Earth’s surface and to infiltration |
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Spring
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represents a place where groundwater flows out of the ground onto the surface
most have water table that intersects with the surface |
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What happens to the shape of the water table as groundwater is pumped?
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After pumping: cone of depression which changes direction of flow
forms because water cannot flow fast enough to replenish the amount of water that is withdrawn from the well In many cones, the water table becomes steeper near the well because water is withdrawn too fast |
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Well
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a hole dug or drilled deep enough to intersect the water table
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How Are Lakes and Wetlands Related to Groundwater?
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Perched above water table with outflow to subsurface
Where water table intersects the surface (normal setting for lakes) Lake on bench (flat area) in topography Lake on bottom of valley, where water table is flat Wetlands can be at water table or perched above an impermeable zone |
