Lecture 9

Question 1

Define a water table

Answer 1

The line of complete saturation above the groundwater. This is a dynamic and changing boundary

Question 2

Define through flow.

Answer 2

Horizontal flow of water within the soul matrix above the water table. This happens when soil becomes saturated and the water moves due to gravity towards a stream or lake

Question 3

Define groundwater flow.

Answer 3

Underground topographic flow of groundwater due to gravity.

Question 4

Define percolation

Answer 4

Vertical movement of water downward through a soil matrix

Question 5

True or False:

The ground water zone is totally saturated

Answer 5

True

Question 6

True or False:

Ground water supplies lakes and rivers but not oceans.

Answer 6

False. It supplies all three

Question 7

Do larger or smaller sediments promote quicker groundwater flow?

Answer 7

Smaller

Question 8

What is unconfined groundwater?

Answer 8

Groundwater not restricted by an impervious layer of rock

Question 9

Define a perched water table.

Answer 9

A water table present above another water table due to an impervious rock layer

Question 10

What happens to confined groundwater.

Answer 10

It becomes pressurized

Question 11

True or False:

An artesian well occurs when pressurized confined groundwater reaches the surface

Answer 11

True

Question 12

What recharges groundwater?

Answer 12

Precipitation percolating down

Question 13

True or False:

Groundwater has a short residence time

Answer 13

False

Question 14

What can intercept precipitation in its way to groundwater?

Answer 14

Vegetation absorbing water from the ground or catching it in the canopy

Question 15

What is infiltration?

Answer 15

Water entering a soil matrix

Question 16

What is the difference between the zone of aeration and the water table?

Answer 16

The water table is complete saturation and the zone of aeration is only partially saturated

Question 17

Name three methods of water energy movement.

Answer 17

Hydroscopic, capillary, gravitational

Question 18

Define hydroscopic movement of water.

Answer 18

Microscopic particle adhesion. Very small scale

Question 19

Define the capillary movement of water.

Answer 19

Held in the pour matrix

Question 20

Define the gravitational flow of water

Answer 20

Water flowing readily through large spaces

Question 21

What is the order of strength in the methods of water movement

Answer 21

Hydroscopic > capillary > gravitational

Question 22

What three things will increase the permeability of soil?

Answer 22

Add gravel under
Sand on the top
Aerate

Question 23

What is porosity?

Answer 23

% volume pore space in a rock or sediment. It is a measure of holding capacity

Question 24

Does clay have a low or high water retention? Why?

Answer 24

High. Because of the larger surface area. Clay is platelets of minerals and lots of water can adhere to this

Question 25

Define hydraulic conductivity.

Answer 25

Ability of water to flow.

Question 26

Define permeability.

Answer 26

The ability of a substrate to transmit water, requires the water to be connected and varies with pore size.

Question 27

Define and aquitard.

Answer 27

A surface not permeable to water

Question 28

Define and aquifer

Answer 28

A substance containing water

Question 29

What makes a well flow?

Answer 29

There must be surface pressure

Question 30

What three things control groundwater movement

Answer 30

Substrate: porosity and permeability Pressure: a function of the weight of the water at a depth Elevation: potential energy above sea level

Question 31

True or False: | Groundwater flows low to high pressure

Answer 31

False

Question 32

Where does water flow when the water table is high?

Answer 32

Down

Question 33

True or false: | Water will flow up towards a low discharge area

Answer 33

True

Question 34

What is hydraulic head?

Answer 34

A function of pressure and elevation that is a length term.

Question 35

What causes a cone of depression?

Answer 35

A well inserted into ground water that drains the surrounding groundwater

Question 36

What is Groundwater?

Answer 36

Water that occupies space in the pores of sediment or rock below the earths surface