King Fahd University of Petroleum & Minerals
Civil Engineering Dept.
CE 331 Engineering Hydrology
HW NO. 6
Spring 07-08
Instructor: Rashid .I. Allayla
Student Name: ________________________
Student No. ___________________________
SCORE: ____________________
Problem 1:
A silty sand sample have the following properties:
 Total mass = 1523.6 g
 Mass of oven dried sample: 1318.3 g
 Total volume of sample: 728.2 cm3
 Density of the solid: 2.7 g/cm3
Calculate:
a) Porosity
b) Volumetric Water Content
c) Dry bulk density
Problem 2:
The following field data was taken from piezometers installed side by side at a single
site (each 100 m apart):
Piezometer:
Elevation at surface (m)
Depth of Piezometer (m)
Depth to water (m)
A
450
150
27
B
450
100
47
C
450
50
36
If A, B and C (m) refer to the points of measurement of piezometers a, b and c.
Calculate:
a)
b)
c)
d)
The hydraulic head at A, B and C (m)
The pressure head at A, B and C (m)
The elevation head at A, B and C (m)
The hydraulic gradient between A and B and B and C.
A
B
450
100 m
C
100 m
423
414
403
400
350
300
Datum
a) Hydraulic head @ A = 423 - 300 = 123 m
B = 50 + (403-350) = 103 m
C = 100 + (414-400) = 114 m
b) Pressure head @ A: 423 – 300 = 123 m
B: 403 – 350 = 53 m
C: 414 – 400 = 14 m
d) Elevation heads: A= 0, B= 50 m and C= 100 m
e) Gradient A to B = (123-103) / 100 = 0.2
f) Gradient B to C = (103-114) / 100 = -0.11
Problem 3:
A soil sample is tested in laboratory. The column has an inside diameter of 10 cm and the
length of the soil sample is 25 cm. With steady flow of Q = 1.7 cm 3 / min, the head difference
between the two manometers is 15 cm. Calculate:
a) The hydraulic conductivity of the sample.
b) The intrinsic permeability k if the water temperature is 30O C
Q = - K A (h2-H1) / L
K = - Q L / A ∆H = - (1.7) (25) / [(π)(52) (-15) = 0.036 cm/min