A LECTURES 1&2

Question 1

Capillary Fringe

Answer 1

Region above water table where water rises due to capillary forces in the porous medium

Question 2

Confining layer

Answer 2

goes over confined aquifer

Question 3

Perched aquifer

Answer 3

unconfined, clay lens stops recharge straight down and forms one, normally not much water

Question 4

vadose zone

Answer 4

unsaturated zone, above water table (includes capillary fringe)

Question 5

Phreatic zone

Answer 5

saturated zone

Question 6

Aquifer

Answer 6

a geological unit that can store and transmit water at rates fast enough to supply reasonable amounts to wells

Question 7

unconfined aquifer

Answer 7

water is in contact with atmospheric pressure

Question 8

confined aquifer

Answer 8

water under pressure due to weight of the upgradient water and confinement of water between impermeable layers

Question 9

aquiclude or aquitard

Answer 9

low permeability layer

Question 10

Porosity

Answer 10

=void volume/volume, effected by grain shape and packing

Question 11

Effective porosity

Answer 11

porosity available for flow

Question 12

Intergranular porosity

Answer 12

Between grains

Question 13

Intragranular porosity

Answer 13

within grains, usually not effective

Question 14

Clay

Answer 14

high porosity
low permeability

Question 15

Limestone

Answer 15

low porosity
high permeability (due to fractures)

Question 16

Secondary porosity

Answer 16

secondary dissolution or structural opening (fractures, faults, bedding planes)

Question 17

Permeability

Answer 17

measures the transmission property of the media and the interconnection of the pores

Question 18

good aquifers have

Answer 18

high permeability surrounded by low permeability units

Question 19

q (specific discharge)

Answer 19

=Q(volumetric discharge or flow rate)/A

Question 20

water flows from

Answer 20

areas of high head to low head

Question 21

dimensionless hydraulic gradient

Answer 21

dh/dl

Question 22

Hydraulic conductivity (K) units

Answer 22

velocity (ms-1)

Question 23

Darcy’s law limitations

Answer 23

doesn’t take into account pore space so area used is much more that area that can be used by the flow

Question 24

linear pore velocity

Answer 24

darcy’s law with ne (effective porosity) added in

Question 25

intrinsic permeability

Answer 25

k=N(dimensionless shape factor)* d^2(grain diameter)

Question 26

Definition of a Darcy

Answer 26

A cube of porous medium with sides of 1 cm length and a permeability of 1 Darcy will produce a flow rate of Q = 1 cm3/s for a pressure differential of P = 1 atm for a fluid with viscosity µ of 1 cP

Question 27

lower limit of darcys

Answer 27

low pressure gradients or permeability
threshold grad to get flow
below certain grad -non linear

Question 28

higher limits of darcys

Answer 28

high hydraulic grad
observed discharge is much less
laminar to turbulent as so permeable