Page 1 of 12
MAIN ASSESSMENT: AUGUST 2021
DATE:
AUGUST 2021
DURATIOIN:
24-HOURS
SUBJECTS:
HYDROLOGY &
TIME:
9:00am (Day 1) to
9:00am (Day 2)
CODE:
CHY21A
WATER ENGINEERING II
INSTRUCTIONAL PROGRAMME:
CWE21AI
DIP ENG. TECH: CIVIL
N. DIP: ENGINEERING: CIVIL
INSTRUCTIONAL PROGRAMME CODE:
DP_CVL; ISNDLS
ASSESSOR:
Mr JPJ Pietersen M Tech Eng. Pr Tech Eng.
MODERATOR:
Mr. CGF Lloyd BSc (Hons) Appl. Sci (Civil Eng.). Pr Tech Eng.
STATIONERY:
1.
Assignment submittal and identification sheet (inclusive of declaration).
2.
eThuto access and any software application for scanning purposes.
3.
Answering book/paper.
INSTRUCTIONS TO CANDIDATES:
1.
Open-book timed (24-hour) online assessment.
2.
A completed and signed ‘Assignment submittal and identification sheet’ must be included in
your answering script.
3.
All the questions must be answered in your own hand writing and in the correct numerical
order. Show all units and calculations and make valid assumptions.
4.
Write neatly and clearly. Avoid unclear pictures, make sure the answering script is clear to
read and properly scanned using appropriate software.
5.
Submit the assignment on eThuto via Safe Assign as a single pdf document or zip-folder
between 07:00am and 9:00am on the scheduled submission date.
6.
A maximum of 3 attempts for submission via Safe Assign are allowed. You will be able to
view your Safe Assign originality report/plagiarism score, which must be limited to <20%.
7.
Professionalism and completeness will contribute 10% towards the final mark.
…………………………………
Assessor’s Signature
…………………………………
Moderator’s Signature
Page 2 of 12
ASSIGNMENT SUBMITTAL AND IDENTIFICATION
Student number:
___________________________________________________________
Surname and initials:
___________________________________________________________
Subject name:
Hydrology & Water Engineering II
Subject code:
CHY21A & CWE21AI
DECLARATION OF OWN WORK:
By submitting my work on this platform, I declare that:

I have completed this assignment/assessment in accordance with the CUT's Code of Academic
Integrity;

All the work included in this assignment/assessment is my own work; and

I did not consult any person or means other than that allowed by the assignment/assessment
instructions.
Signed:
___________________________________________________________
Date:
___________________________________________________________
…………………………………
Assessor’s Signature
…………………………………
Moderator’s Signature
Page 3 of 12
Complete ONLY the questions marked with an “X” next to your student number:
206201613
213077418
213087898
214049213
215144134
216001408
216005155
216005676
216008712
216009713
216010683
217000627
217003846
217003879
217006729
217007074
217007730
217011280
217011594
217012694
217013045
217013310
218000878
218000976
218001859
218004069
218004207
218005073
218005729
218005914
218006062
218006768
218007118
218008703
218010486
218010808
218011694
218012226
218014371
218014918
219000757
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
2
X
X
X
X
X
X
X
X
X
3
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
…………………………………
Assessor’s Signature
4
X
X
X
X
X
X
X
Questions (6 x 15 = 90)
5
6
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
7
X
X
X
X
X
X
X
8
X
X
X
X
X
X
X
X
X
X
9
10
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
…………………………………
Moderator’s Signature
X
X
X
Page 4 of 12
1
219001273
219002088
219002214
219002439
219002947
219003490
219003594
219003731
219004743
219004967
219005288
219007794
219008583
219008660
219009418
219009933
219010053
219010308
219010611
219012846
219013586
219013735
219013744
219014039
219014045
219014074
219014192
219014306
219014398
219014437
219014569
219014591
219014813
219014929
219014945
219015334
219015372
219015374
219015553
219015711
219015735
219015801
220000805
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
2
X
X
X
X
X
X
X
X
3
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
…………………………………
Assessor’s Signature
4
X
X
X
X
X
X
Questions (6 x 15 = 90)
5
6
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
7
X
X
X
X
X
X
X
8
X
X
X
X
X
X
X
X
X
X
9
10
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
…………………………………
Moderator’s Signature
X
X
X
Page 5 of 12
220001396
220001410
220001559
220001662
220001836
220001878
220002602
220003368
220004423
220005313
220005632
220005982
220007388
220007549
220008006
220008333
220008707
220011258
220011392
220013028
220013171
220013400
220014049
220014365
220014458
220014653
220015042
220015221
220015727
220015800
220015848
220017026
220019055
220019728
220019786
220020056
220021275
220021662
220022632
220023308
220026194
220027767
220029143
220029789
1
2
3
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
…………………………………
Assessor’s Signature
4
X
X
X
Questions (6 x 15 = 90)
5
6
7
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
8
X
X
X
X
X
X
X
X
9
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
10
X
X
X
X
X
X
X
X
X
X
X
X
…………………………………
Moderator’s Signature
X
X
X
X
X
Page 6 of 12
220030444
220030470
220031348
220032768
220033620
220035782
220036020
220036404
220037013
220037476
220038102
220038862
220039191
220040151
220040205
220040810
220041299
220041421
220041563
220044294
220044873
220046121
220046437
220046907
220047976
220048443
220049606
220049634
220049679
220049681
220049695
220049740
220049755
220049777
220049781
220049789
220049803
220049816
1
X
X
X
X
2
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
3
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
…………………………………
Assessor’s Signature
Questions (6 x 15 = 90)
5
6
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
4
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
7
X
8
X
X
X
X
9
10
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
…………………………………
Moderator’s Signature
X
X
X
X
X
Page 7 of 12
QUESTION 1
[15]
The long-term wind speed record is available for heights at 9.5m (8.9m/s) and 16.5m (9.30m/s)
respectively. For future calculations of evaporation the wind speed is required at heights of 2m, 4m,
6m, 8m, 10m and 12m. use the information and determine / derive the following:
a) Exponent value,
(4)
b) Windspeed at each height listed above, and
(6)
c) Windspeed algorithm that can be used for future windspeed calculations
(5)
QUESTION 2
[15]
In your own words, elaborate on alternative methods available to treat water for human consumption.
The methods should not form part of the conventional methods of treating water, but should rather
focus on greener, more efficient, and more sustainable than the conventional ways of treating water.
Include sketches, figures, flow charts ect. to support your discussion. NO COPY AND PASTE FROM
THE INTERNET.
QUESTION 3
[15]
Your company is responsible for the determination of the 1:50 return period design flood. You are
appointed to perform the necessary calculations and should use the SCS-method, ALSO make use of
both original Lag-time equations. The catchment characteristics are as follows:
 Size of catchment:
18.8km²
 Longest watercourse:
3880m
 Average slope of catchment and longest water course:
2.40%
 Time of concentration
3.10h
 24-hour maximum precipitation:
177mm
…………………………………
Assessor’s Signature
…………………………………
Moderator’s Signature
Page 8 of 12
Use the (i) information in the table below and (ii) the SCS land-uses table in your notes in order
to determine relevant CN value.
Hydrological
Land-use
Area (km²)
Small grain – planted on contour: winter
7.23
B
Sugar cane - Straight row: > 75% cover
3.36
C
Sugar cane - Planted on contour: > 75% cover
5.5
C
Urban/ suburban Land-uses – Roads: Gravel
2.71
D
soil groups
QUESTION 4
[15]
Study the 1: 50 000 map (Annexure A) and answer the following questions:
a) Delineate the catchment contributing to flow at point A,
(7)
b) Plot the main water course profile in Excel and determine the average main water course slope
by making use of the 10-85 method, and
(5)
c) Estimate the approx. catchment area in km2
(3)
QUESTION 5
[15]
A quaternary catchment (C52E) within the C5 secondary drainage region has 10 representative
rainfall stations and is illustrated in Annexure B. Study the sketch (Annexure B) and the information in
the Table below (C52E rainfall data) and answer the following questions:
a)
Prepare usable polygons based on the Thiessen polygon method,
(10)
b)
Estimate the average MAP by making use of the Arithmetic mean method.
(5)
Attach Annexure B as part of your answer.
Rainfall Stations
MAP
Rainfall Stations
MAP
0293792W
0294500W
0293622W
0294052W
0294233W
536
553
500
428
471
0294417W
0293597W 0293597A
0262271W
0261722W
0261789W
506
529
435
534
551
…………………………………
Assessor’s Signature
…………………………………
Moderator’s Signature
Page 9 of 12
QUESTION 6
[15]
6.1 If you are given a continuous discharge of a stream over a period of a few years, discuss how
you separate runoff and base flow using the master depletion method. Make use of sketches to
illustrate the method.
(3)
6.2 Discuss in your own words at least five physical properties affecting the quality of drinking water
supply.
(5)
6.3 Discuss the important parameters affecting the concentration of organic, nutrient and solid
materials in domestic wastes.
(7)
QUESTION 7
[15]
The flow in a river, flowing into a reservoir, was measured over many years and the average flow for
each month is given in the following table. Determine the capacity of the reservoir required to
maintain a demand equal to the average flow during the years if the reservoir is full in the month of
March start with. Also, determine the amount of water spilled off. Flow is in 106 m3/month.
Month
Jan
Feb
Mar
Apr
May
June
July
Aug
Sep
Oct
Nov
Dec
Flow
16.04
12.54
9.9
6.74
3.37
1.1
0.28
0.31
0.48
4.1
12.59
17.66
QUESTION 8
[15]
A catchment is undergoing a prolonged drought period. The discharge of a river within the catchment
is 286m3/s after 10 days without rain and 111m3/s after 33 days without rain. Estimate the discharge
after 85, 90 and 95 days without rain.
QUESTION 9
[15]
The recession limb of a hydrograph, listed below, is to be divided into runoff and base flow. Use a 6hseparation technique to determine the point of groundwater depletion to separate the surface runoff
from the base flow.
…………………………………
Assessor’s Signature
…………………………………
Moderator’s Signature
Page 10 of 12
Discharge data of hydrograph
Time (hours)
Q (m3/s)
24
19.2
27
15.1
30
12.2
33
10
36
8.3
39
7
42
5.8
45
4.9
48
4.1
QUESTION 10
[15]
Development of a new reservoir is proposed in a mountainous region at latitude of 20°N for water
supply. June appears to be the critical month and average values of various parameters in this month
are given as follows:

Air temperature:
24°C

Relative humidity:
60%

Wind speed @ 2m:
2.5m/s

Cloud cover:
10%

Reservoir surface area:
300 km²

Average inflow from a stream into the reservoir in June: 28m 3/s.
Angot’s values of short-wave radiation (g cal/cm²/ day)
Latitude
N 90
80
60
40
20
Equator
20
40
60
80
S 90
Jan.
0
0
86
358
631
844
970
998
947
981
995
Feb.
0
3
234
538
795
963
1020
963
802
649
656
Mar.
55
143
424
663
821
878
832
686
459
181
92
Apr.
518
518
687
847
914
876
737
515
240
9
0
May
903
875
866
930
912
803
608
358
95
0
0
June
1077
1060
983
1001
947
803
580
308
50
0
0
July
944
930
892
941
912
792
588
333
77
0
0
Aug.
605
600
714
843
887
820
680
453
187
0
0
Sept.
136
219
494
719
856
891
820
648
403
113
30
Oct.
0
17
258
528
740
866
892
817
648
459
447
Nov.
0
0
113
397
666
873
986
994
920
917
932
Dec
0
0
55
318
599
829
978
1033
1013
1094
1110
Year
3540
3660
4850
6750
8070
8540
8070
6750
4850
3660
3540
Calculate the expected change in storage in the month of June (in m3/month).
TOTAL MARKS: 90 + 5 (Professionalism) + 5 (Completeness) = 100
END OF ASSIGNMENT
…………………………………
Assessor’s Signature
…………………………………
Moderator’s Signature
Page 11 of 12
Annexure A: 1:50 000 Map (NTS)
A
meter
…………………………………
Assessor’s Signature
km
…………………………………
Moderator’s Signature
Page 12 of 12
Annexure B: Catchment C52E
$
0293792W
Legend
D
$
C52E Centroid
Rainfall_stations
C52E Rivers
C52E
$
$
0293622W
$
0294052W
$
0294233W
D
$
0294500W
$
0294417W
0293597W 0293597A
$
$
0262271W
0261722W
$
0261789W
…………………………………
Assessor’s Signature
…………………………………
Moderator’s Signature