B&C Groundwater fundamentals

Question 1

Potential Energy

Answer 1

energy stored in a system

Question 2

Groundwater flow

Answer 2

mechanical process
flow forces must overcome friction between porous media and fluid

Question 3

in groundwater the main sources of potential energy

Answer 3

position (GPE), and pressure

Question 4

unsaturated zone potential energy

Answer 4

due to attraction between soil and water (moisture potential)

Question 5

Piezometer

Answer 5

a borehole only open at the bottom
tell us the pressure at the opening

Question 6

isotropic

Answer 6

material properties same in all directions
k is scalar

Question 7

work done per unit mass

Answer 7

=acceleration * distance

Question 8

hydraulic potential to hydraulic head

Answer 8

divide everything by gravity

Question 9

z

Answer 9

elevation head- from datum to bottom of piezometer

Question 10

p/(g*rho)

Answer 10

pressure head - from bottom of piezo to top of water in piezo

Question 11

homogeneous

Answer 11

same properties in every location of the unit

Question 12

flow in an anisotropic medium

Answer 12

flow is deflected away from the gradient direction towards the direction with least flow resistance

Question 13

Piezometric surface

Answer 13

connects all points to which water would rise if piezometers were installed
unconfined aquifer this is water table
hieght determined by the hydraulic head

Question 14

Artesian well

Answer 14

Piezometric surface about ground surface

Question 15

Flow direct to equipotential head lines

Answer 15

perpendicular in an isotropic homogen aquifer

Question 16

Flow net

Answer 16

the network of equipotential lines and flow lines belonging to a specific aquifer

Question 17

flow net assumptions

Answer 17

homogeneous, isotropic, fully saturated aquifer & flow boundary conditions

Question 18

no flow boundary

Answer 18

flow parallel to boundary
equipotential perpendicular to boundary

Question 19

constant head boundary

Answer 19

flow perpendicular to boundary
equipotential are parallel to boundary

Question 20

effective stress (sigma e)

Answer 20

portion of total stress not borne by the fluid

Question 21

compressibility

Answer 21

strain/stress

Question 22

beta

Answer 22

compressibility of water

Question 23

alpha

Answer 23

compressibility of porous medium, rearrangement of grains

Question 24

compressibility is inversely dependent on

Answer 24

grain size

Question 25

why is k aquitard < k aquifers

Answer 25

aquifers can transmit water quickly so if water pumped out head will drop quickly in aquifers
compression much slower in aquitards

Question 26

Transmissivity T

Answer 26

= bK
amount of water that can be transmitted horizontally through a unit by the full saturated thickness of the aquifer

Question 27

Ground water induced compaction

Answer 27

thick sequences poorly consolidated sediments with interbedded aquifers and aquitards

Question 28

storativity values

Answer 28

very small <0.005

Question 29

spring discharge controlled by

Answer 29

input events e.g. lots of rain

Question 30

shape of hydrograph controlled by

Answer 30

flow through different pathways that have different K and velocities