Chapter 10 Flashcards
H2O stored in the where?
ground
Where are the most fresh H2O
near or in glaciers
How does water get into the ground
infiltration by precipitation
Infiltration
through pores of permeable rocks
(look at image)
Three positions of H2O in the ground
-Zone of aeration
-Zone of saturation
-Water table:
Positions H2O ground:Zone of aeration (or unsaturated zone)
-Top layer of soil with air and water
above the water table where the pore spaces among soil particles and rock formations are filled with air
Positions H2O ground:Zone of saturation (Saturated zone)
-Lower layer, below water table - all space (pores) occupied by H2O
Positions H2O ground:Water Table
Top of saturated zone not necessarily flat, follow topography
*Aquifer
water-bearing rock readily transmits water to wells and springs,
Porosity is enough to store water
Permeability: ABility to trnasmit
(look at image)
aquifer must have both: poristy and permabibs
(sand, limestone, metamorphic rocks)
Aquitard
-impermeable body of rock( opposite to aquifer)
(clay)
soak up the water and dont let it transmit
Confined Aquifer:
-An aquifer trapped by two aquitards (usually under pressure)(look at picture)
If a confined Aquifer when inteserted by borehole can form what?
(a)Artesian Well (b) Flowing Artesian Well
Unconfined Aquifer:
exposed at surface (not under pressure)(look at picture)
Recharge Areas:
the place where water is able to seep into the ground and refill an aquifer because no confining layer is present
where H2O gets into aquifer (usually high elevation)
Discharge Areas:
where H2O gets out of aquifer (usually low elevation, valleys)
Aquifers contain large volumes of
H2O
*In the US, Ground H2O within 1 km is more than
30 times the volume of all H2O in lakes,
rivers & reservoirs on the surface
-Withdrawal: is in
liters/s, gallons/s or m3/s or min, etc.
Aquifer problems : -Water Balance:
Aquifer use should maintain water balance
Inflow = Outflow
*Often, balance is not maintained
Could be natural or artificial (human induced)
-Natural: Less recharge than discharge
-Human induced: Too much pumping
This could also cause dry wells
An examples of a Aquifer: Ogallala Aquifer:
*World’s largest freshwater body
* Underlies 8 states in HIGH PLAINS REGION
* In the past had 16 times H2O than all lakes, streams, rivers & marshes on earth
* H2O recharged from glacial melt H2O about 15000 years ago
* Used mainly for agriculture & domestic
Ogallala Aquifer: Problems
- More water pumped than recharged
- Water table declined, if aquifer dries up
a.Farming products will be reduced
b. Domestic use will stop, etc.
*Depth of water in 1930 was 20 m, BUT now (1987) about 3m
*WHY? Cone of depressioin
*Groundwater Movement:Direction:
From high hydraulic head to low hydraulic head
Groundwater Movement:Quantity:
According to Darcy’s Law: the principle which governs the movement of fluid in the given substance. Darcy’s law equation describes the capability of the liquid to flow via any porous media like a rock.
Water Pollution:
*Urbanization pollutes surface & groundwater
Water Pollution:
Pollution:
any change in water quality that affects:
(a) living organisms
(b) makes H2O unsuitable for uses
Water Pollution:
Contamination: The standard?
Concentration of pollutant just above EPA standard
Water Pollution:
Pollution: FREE BEE
Much above standard
Water population change can be…?
physical, chemical, biological
Any change that uses up oxygen at the expense of fish, other living organisms
- Can be POINT or NON-POINT sources
Point Sources:
-Factories, power plants, sewage treatment plants, coal mines, oil well, etc.
-(All discharge through specific locations.)
Non-Point Sources:
-Scattered/diffuse sources
-Runoff from farm fields, gardens etc. (seasonal)
Treatment of Pollution (Sewage)
-Human sewage is treated in stages –Primary treatment, Secondary treatment
. Tertiary
PRIMARY TREATMENT -
First stage in treatment, & it removes solids raw
polluted source.
SECONDARY TREATMENT -
Remaining solid is removed & decomposed using bacteria
TERTIARY TREATMENT -
Removes inorganic minerals & plant nutrients
(Tertiary treatment produces water that is usable for drinking.)
-e.g., polluted water can also be disposed off in deep water wells
Some Effects of Water Pollution
Water pollution can cause health hazards
most likely PATHOGENS (i.e., disease causing
organisms), bacteria and viruses
*It is very difficult to detect pathogens, therefore, water is usually analyzed for
COLIFORM BACTERIA that live in human intestine & those of other animals
- When found coliform bacteria indicate the presence of FECES.
Table salt:
is a pollutant & can kill if taken in high enough quantity.
Warm water:
is considered as a pollutant & make life difficult for some living organism.
Ocean water
: is pollutant & has bad effects on organisms & humans.
