KIGALI INSTITUTE OF SCIENCE AND TECHNOLOGY
FACULTY OF ENGINEERING
DEPARTMENT OF CIVIL ENGINEERING & ENVIRONMENTAL TECHNOLOGY
END OF SEMESTER II EXAMINATIONS
ACADEMIC YEAR: 2012-2013
YEAR OF STUDY:
SEMESTER:
2
SUBJECT CODE & NAME:
NO. OF STUDENTS:
II
Programme: Full Time
Part Time
√
WEE 3221 ENGINEERING HYDROLOGY
DURATION: 2hrs
123
DATE OF SUBMISSION:
MAX. MARKS: 60
20/03/2013
NAME OF INTERNAL EXAMINER:
TEL:
EXAMINATION PERIOD: APRIL 2013
MAJORO Felicien
+250788484054
E-MAIL:
f.majoro@kist.ac.rw
SIGNATURE:
Submitted
(i) Syllabus
√
(ii) Main Exam Qns.
√
(iii) Marking scheme
√
(iv) Supp exam Qns. √
(v) Marking scheme
√
Head of Department:
Date:
KIGALI INSTITUTE OF SCIENCE AND TECHNOLOGY
FACULTY OF ENGINEERING
DEPARTMENT OF CIVIL ENGINEERING AND ENVIRONMENTAL TECHNOLOGY
INTERNAL MODERATOR’S REPORT
DETAILS OF MODERATOR
Name of the Moderator: Ms UWIMPUHWE Charlotte
Designation: Assistant Lecturer
Area of Specialisation: Land and Water Sciences
DETAILS OF MODERATING SUBJECT
Module Code and Title:
WEE 3221 Engineering Hydrology
Year of Study: 2 Sem: II
Academic Year: 2012-2013
DETAILS OF MODERATION
Sl.No
DESCRIPTION OF ASSESSMENT
COMMENTS,if any
1.
Coverage of Syllabus
OK
2.
Standard and Level of Question Paper
OK
3.
Allocation /Distribution of Marks
OK
4.
Allocation of Time
OK
5.
Qualitative Treatment (Theory)
OK
6.
Quantitative Treatment (Problem)
OK
7.
Correlation between Qualitative and
Quantitative
OK
Have comments been incorporated in the question paper or marking scheme by the staff? Yes
Signature of Moderator:
Date:
No

INDICATIVE CONTENT
WEE 3221 ENGINEERING HYDROLOGY
UNIT I INTRODUCTION
Definition and scope, Hydrological cycle, World water balance, Practical applications, Historical
development.
UNIT II PRECIPITATION
Introduction, Formation of precipitation, Forms of precipitation, Types of precipitation, Weather
systems for precipitation, Measurement of rainfall, Presentation of rainfall data, Mean
precipitation over an area, Estimation of missing precipitation records, Double mass curve.
UNIT III EVAPORATION
Definitions, Mechanisms, Measurements, Equipment used, Empirical methods used to determine
evaporation.
UNIT IV INFILTRATION
Infiltration process, infiltration capacity, measurement of infiltration, infiltration capacity values,
infiltration indices.
UNIT V STREAM FLOW MEASUREMENTS
Introduction, Measurement of stage, Measurement of discharge: current meter, dilution methods,
stage discharges, electromagnetic and ultrasonic methods, Indirect methods, Stage discharge
relations, Extension of rating curve and its validity, Stream flow routing.
UNIT VI RUNOFF
Introduction, Components of runoff, Factor affecting runoff, Basin yield, Rainfall-runoff
relationship, Peak runoff, Flow mass curve, Determination of runoff by mathematical models.
UNIT VII FLOOD HYDROGRAPH
Components of hydrograph, Factor affecting flood hydrograph, Base flow separation, Effective
rainfall, Unit hydrograph, Instantaneous unit hydrograph, Unit hydrograph of different durations.
UNIT VIII DESIGN FLOOD ESTIMATION
Introduction, Definitions: Flood, Most Probable Flood, Design Flood. Various methods used for
Design Flood Estimation. Rational method, Weibul method, Gumbel method and Log-Pearson
type III Distribution. Risk in selecting a design flood and its return period. Flood Frequency
analysis.
UNIT IX FLOOD CONTROL METHODS
Various Flood control methods: Structural measures & Non structural measures. Environmental
issues of flood control projects: Positive impacts & Negative impacts. Econmics of Flood control
projects: Benefit/cost analysis.
UNIT IX HYDROLOGIC ROUTING
Definition, reservoir routing, channel routing: prism storage, wedge storage; hydraulic method;
numerical method.
MAIN EXAM
KIGALI INSTITUTE OF SCIENCE AND TECHNOLOGY
Avenue de l'Armée,
B.P. 3900 Kigali,
Rwanda
INSTITUTE EXAMINATIONS -SEM:II
ACADEMIC YEAR 2012-2013
FACULTY OF ENGINEERING
DEPARTMENT: CIVIL ENGINEERING & ENVIRONMENTAL TECHNOLOGY
YEAR: 2
SEMESTER: II
MODULE:
DATE:
GROUP: CE & WEE
WEE 3221 ENGINEERING HYDROLOGY
/ 04 /2013
TIME: 2hours
MAXIMUM MARKS = 60
INSTRUCTIONS
1. This paper contains FOUR (4) questions.
2. Answer THREE (3) Questions only:
Question ONE (1) from Section “A” is Compulsory and Answer any TWO (2) from Section
“B”
3. All questions carry equal marks.
4. No written materials allowed.
5. Do not forget to write your Registration Number.
6. Write all your answers in the booklet provided
7. Do not write any answers on this questions paper.
8. Start each question in a NEW page
Section A: Q1 is compulsory
QUESTION 1.(20 marks i.e 4 marks for each sub question)
With a neat sketch,
(i)
What do you understand by hydrological budget?
(ii)
Write and express the hydrologic budget of surface water system;
(iii) Write and express the hydrologic budget of groundwater system?
(iv)
Deduce the system hydrologic budget of a basin;
(v)
The water budget terms for a lake included precipitation (P) of 48.26mm/year,
evaporation (E) of 38.1mm/year, surface water inflow (Qin)of 0 mm/year, surface out
flow( Qout) of 441.96mm/year, and the change in lake volume (∆𝑠) of 0 mm/year.
Determine the net groundwater flow.
Section B: Attempt any 2 Questions from the following Q2, Q3 & Q4
Question2 (20marks)
(i)
Draw a labeled neat sketch of Symon’s non-recording raingauge (2marks).
Describe its working principle (2marks).
(ii)
Rain-gauge station D was inoperative for part of a month during which a
storm occurred. The storm rainfall recorded in the three surrounding stations
A, B and C were 8.5, 6.7and 9.0 cm, respectively. If the average annual
rainfall for the stations are 75, 84, 70 and 90 cm, respectively, estimate the
storm rainfall at station D. (2marks)
(iii) The followings are the rain gauge observations during a storm. Prepare a table
(2marks) and draw the mass curve (2marks) and the rainfall hyetograph
(2marks).
Time since the
commencement
of the storm
(min)
5
10
15
20
25
30
35
40
45
50
Accumulated
rainfall (cm)
0.1
0.2
0.8
1.5
1.8
2.0
2.5
2.7
2.9
3.1
(iv)
Compute the daily evaporation from a Class A pan (2marks) if the amounts of water
added to bring the water level to the fixed point are as follows:
Day
Rainfall (mm)
Water (mm)
added (+)
or removed(-)
1
14
2
6
3
12
4
8
5
0
6
5
7
6
–5
3
0
0
7
4
3
What is the evaporation loss of water in this week from a lake (2marks) of surface
area of 640 ha, assuming a pan coefficient of 0.75?
(v)
The total observed runoff volume during a storm of 6-hr duration with a
uniform intensity of 15 mm/hr is 21.6 x 106 m3 . If the area of the basin is 300 km2,
find the average infiltration rate (2marks) and the runoff coefficient for the basin
(2marks).
Question3. (20pts i.e. 4 marks each sub-question)
(i)
A culvert is proposed across a stream draining an area of 185 ha. The catchment has a
slope of 0.004 and the length of travel for water is 1150 m. Estimate the 25 years
flood if rainfall is given by:
𝑖=
1000 𝑇𝑟 0.2
(𝑡 + 20)0.7
where i(mm/hr); Tr(years) and t(min). Assume a runoff coefficient of 0.35.
(ii)
(iii)
(iv)
(v)
The analysis of a 30 year flood data at a point on a river yielded xavg = 1200 m3/s and
Sx = 650 m3/s.
For what discharge would you design a hydraulic structure at that point to provide
95% assurance that this structure will not fail in the next 50 years?
List and discuss briefly at least 8 flood control methods.
List and discuss briefly various (at least 4) environmental issues of flood control
projects;
What do you understand by “Sustainability of a WRDP”?
Question 4. (20pts i.e 5 marks each sub-question)
The inflow hydrograph readings for a stream reach are given below.
The Muskinghum coefficients are K = 36hr and x = 0.15.
Route the flood through the reach and determine the outflow hydrograph.
Determine also the reduction in peak and the time of peak of outflow.
NOTE: The outflow at the beginning of the flood may be taken as the same as the inflow.
Time
(hours)
Inflow
(cumecs)
Time
(hours)
Inflow
(cumecs)
(i)
(ii)
(iii)
(iv)
0
12
24
36
48
60
72
84
96
108
120
24
45
88
272
342
288
240
198
162
133
110
132
144
156
168
180
192
204
216
228
240
-
90
79
68
61
56
54
51
48
45
42
-
1
Taking the routing period as 12 hr = 2 day, compute the coefficients c0, c1 and c2 of
the routing equation.
Fill the stream flow routing table by Muskingum method.
Provide the routing curves by plotting the inflow and the outflow hydrographs on the
same graph.
Determine the peak travel time (i.e the time lag) and the reduction in peak discharge.