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Flashcards in Groundwater Deck (43)
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1

Roughly _____% of Canada's population is reliant on groundwater

25-40%

2

Define Groundwater

water that lies beneath the surface

3

Ground water makes up for __% of the hydrosphere's fresh water, while glaciers make up for ___%

22% and 77%, respectively

4

___% of total precipitation infiltrates the ground and sends up as ground water

15%

5

True or False: ground water is static

False; it is slow moving

6

True or False: groundwater is found most commonly in underground lakes and rivers

True, but barely. It can occur, but is extremely rare

7

Where is groundwater most commonly found

pores of sediment and soil
fractures of bedrock

8

Porosity

percentage of voids or pore space (vs total volume)

9

What is porosity used to determine?

How much groundwater can be stored

10

How to measure porosity

Take a column with a toal volume of 1000 mL and fill it with dry sand (dry sand has a porosity filled with air). replace the air with water. The porosity=volume water/Volume total

11

Permeability or Conductivity

Capacity of rock or sediment to transmit a fluid
(connected pores give a rock permeability)

12

Specific yield

% that can drain by gravity

13

Specific retention

% that cannot drain by gravity

14

Distribution of ground water is found in what three places?

1) Unsaturated zone
2) Water Table
3) Zone of saturation

15

Unsaturated zone

-above water table
-voids filled by water and air
-water is under suction (negative pressure) due to capillary forces (think TLC)
-water cannot be pumped by wells

16

Water Table

-Upper limit of zone of saturation
-surface of water level in ground
-depth varies seasonally

17

Zone of Saturation

-below water table
-all voids are filled with water
-water is under positive pressure and can be sucked up by wells

18

Pressure distribution

unsat:
a) Patmos. P
b) water under (+) pressure

19

What factors control infiltration?

1) precipitation
2) slope
3) geological material
3) vegetation

20

In what three places is groundwater stored?

1) Aquifer
2) Acquitard
3) Aquiclude

21

Aquifer

permeable rock layer or sediment that stores and transmits groundwater

22

Acquitard

semi-permeable rock layer

23

Aquiclude

impermeable rock layer (exCLUDEs water)

24

Types of aquifers

Unconfined and confined

25

Unconfined aquifer

-no confining layer
-groundwater is not under pressure
-top of water table moves freely up and down

26

Confined aquifer

-sandwiched between 2 confining layers (usually inclined to allow recharge)
-groundwater is under pressure
-top of water table is above confined aquifer

27

Types of wells

Non-flowing artesian well and flowing artisan well

28

Non-flowing artesian well

water table (pressure surface) of a confined aquifer lies below ground level (pressure is not great enough to bring water to the surface)

29

Flowing artesian well

Water table of a confined aquifer rests above ground level; water reaches ground surface using natural pressure of the confined aquifer

30

What is the general pattern of movement?

recharge (high) --> discharge (low)