Week 3

Question 1

Unconfined aquifer =

Answer 1

Aquifer with free water surface as upper boundary (water table/phreatic surface) at which P = atmospheric

Question 2

Confined aquifer =

Answer 2

Confined b/w 2 aquitards/cludes = P in aquifer everywhere greater than atmospheric

Question 3

Valley aquifers in temperate climates

Answer 3

Porous and permeable soil

Water table highest beneath hills
- infiltrates and builds up more further away from river
Groundwater drains to topographic lows (river)

Question 4

Groundwater divide =

Answer 4

Catchment boundary

Q = 0

Question 5

Valley aquifers in arid zones

Answer 5

Less rainfall, surface recharge ~0

Water table highest beneath valley (river bed)
Water infiltrates through river bed

Question 6

Homogeneous =

Answer 6

Independent of position in geological formation K (x,y,z)=c(onstant)

‘space’

Question 7

Heterogeneous =

Answer 7

Dependent on position in geological formation K(x,y,z) x=x c

‘space’

N.B. K = hydraulic conductivity

Question 8

Isotropic =

Answer 8

Independent of direction

K x=x f(a)

N.B. K = hydraulic conductivity

a = angle b/w horizontal and direction of measurement

Question 9

Anisotropic =

Answer 9

Dependent on direction

K = f(a)

K = hydraulic conductivity

Question 10

Transversely anisotropic

Answer 10

Layered formation, K can be considered as having only horizontal and vertical components

Kx = Ky x=x Kz

Question 11

Steady state flow in a confined aquifer, assumptions

and in an unconfined aquifer

Answer 11

Homogeneous aquifer i.e. K constant

S-S flow conditions i.e. Q constant and uniform

1D flow

Constant boundary heads

Question 12

Steady state flow in an unconfined aquifer with recharge, assumptions

Answer 12

Homogeneous aquifer i.e. K constant

S-S flow conditions i.e. Q constant and uniform

1D flow

Constant boundary heads

UNIFORM AND CONSTANT RECHARGE

Question 13

Steady state flow in a confined aquifer with unequal boundaries, basic gist

Answer 13

1. Darcy’s Law
2. Integrate both sides
3. Use constraints

–> flow rate is linearly proportional to hydraulic head

Question 14

Steady state flow in an unconfined aquifer with unequal boundaries, basic gist

Answer 14

1. Darcy’s Law
2. Integrate both sides
3. Use constraints

N.B. A=Bh b/c H is not constant

Question 15

Steady state flow in an unconfined aquifer WITH RECHARGE and unequal boundaries, basic gist

Answer 15

1. Mass conservation focussing on the control slice
2. Integrate dQ/dX = expression for Q
3. = to Darcy’s law
4. Integrate both sides w.r.t x
5. Eliminate both constants with boundary conditions
6. Substitute constant in 2’s expression for Q
7. Rearrange

Question 16

Steady state flow in an unconfined aquifer with WITH RECHARGE and equal boundaries

Answer 16

Think like with unequal boundaries but ho-h1 = 0 so first part of equation cancels

Question 17

Per unit length B =?

Answer 17

1

Question 18

“…water does not travel from the sea to the lake” x =?

Answer 18

0

Question 19

Upper aquifer surface when CONFINED must be ? both water sources

Answer 19

BELOW (diagram)