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CORK INSTITUTE OF TECHNOLOGY
INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ
Semester 1 Repeat Examinations 2010/
Module Title: Water Engineering
Module Code: CIVL
School: Building & Civil Engineering
Programme Title: Bachelor of Engineering (Honours) in Structural Engineering
Programme Code: CSTRU_8_Y
External Examiner(s): Dr. Mark Richardson, Mr. John O’ Mahony Internal Examiner(s): Dr. J. Harrington
Instructions: Answer Question No. 1 and Two Other Questions
Duration: 2 Hours
Sitting: Autumn 2011
Requirements for this examination:
Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination paper. If in doubt please contact an Invigilator.
Q1. (a) Discuss water treatment (with the aid of diagrams where appropriate and give one example of a local application in each case ) under the following headings: (i) Raw Water Storage (4 marks) (ii) Screening (6 marks) (iii) Rapid Gravity Filtration (6 marks)
(b) A water supply scheme is required for an area which includes a 3 teacher, 80 pupil national school, an estimated eventual maximum number of houses of 25 and a single large dairy farm with 100 dairy cows and up to 25 calves. Take dairy cow water demand as 150 l/head/day, calf water demand as 22 l/head/day and 50 l/day per pupil and staff.
The water supply takes water from a nearby river, which can supply the community all year round. The lowest estimated water level in the river is +3m O.D., the highest is +7.5m O.D.
A pump is required for supply and must provide the required flow at a minimum pressure head of 10m. Determine the pump requirements given information on two points within the area to be supplied:
Point A (an intermediate point within the supply scheme) Distance from Supply Point: 1500m, Discharge Elevation: +17m O.D. Point B (the furthest point within the supply scheme) Distance from Supply Point: 1750m, Discharge Elevation: +16m O.D. Use the attached flow nomogram for a polyethylene pipe. (18 marks)
EQUATIONS
Open Channel Flow
Chezy Eqn.: v C m S 0
Manning Eqn.: 1 / 2 0
2 / 3 S n
m v
1 / 3 2
2
gB
Q
dc
Backwater Curves
gd
v
s i dl
dd 2 1
Sediment Transport
Vertical Suspended Sediment Profile:
ku *
v
r
r r
s
Y y
Y y y
y C
C
Shear Velocity: u * (^) gmS 0
Stoke’s Law:
18
(^2) s ^ p
gd v
0 gmS 0
cr 0. 056 p gD 50
Shields Eqn.:
0
2 (^100) gD
qS q p p
cr s
