TECHNICAL GUIDE No.1
Estimation of Future Design
Rainstorm under the Climate
Change Scenario in Peninsular
Malaysia
Research Centre for Water Resources &
Climate Change
National Hydraulic Research Institute of Malaysia
Ministry of Natural Resources & Environment
Feb. 17, 2013
NAWMI, JPS
 Part 1 : HP1 (2010)
 Part 2 : NAHRIM Tech. Guide No.1
 Chap. 1 – 1.2 (problem state. &
1.3 (objective)
 Chap. 2 – Approach & Methodology
 Chap. 3 – Results & Findings
 Part 3 : Chap. 4 - Worked Example
Part 1 : HP1 (2010) -1/3
TASK 1 (T1)
Data Mining &
Assembly
TASK 2 (T2)
Choice of Rainfall
Freq. Model
TASK 3 (T3)
TASK 4 (T4)
Choice of Prob.
Distribution
Method of Parameter
Estimator
OUTLIER CHECKING
Data:
PD Series & AM
Series
PD Series: Low &
High Return
Period
3P-GPA or
2P-GPA/EXP
L-MOMENTS
(LMOM)
AM Series: High
Return Period
(>1yr)
3P-GEV
or 2P-EV1
METHODS OF
MOMENT (MOM)
OPTIONAL for
UNGAUGED
ONE-STEP LEAST
SQUARE
METHOD
Part 1 : HP1 (2010) -2/3
TASK 1 (T1)
TASK 2 (T2)
TASK 3 (T3)
TASK 4 (T4)
GOOD
PERFORMANCE :
BIAS
RANDOM
NUMBER
ROBUSTNESS
ANALYSIS :
BIAS & RMSE
ACCURACY :
ROOT MEAN
SQUARE ERROR
BEST FIT/
BEST
FIT/
APPROPRIATE
APPROPRIATE
MODEL
MODEL
3P-GPA/LMOM
3P-GPA/LMOM
3P-GEV/LMOM
3P-GEV/LMOM
2P-GPA/EXP/LMOM
2P-GPA/EXP/LMOM
2P-EV1/LMOM
2P-EV1/LMOM
2P-EV1/MOM
2P-EV1/MOM
3P-GEV/OS-LSM
3P-GEV/OS-LSM
TASK 5
(T5)
Estimation
the
Estimationofof
Design Storm of Low
Design
andthe
High
Return
Period
Rainstorm
TASK 6
(T6)
Construction and
Math. of atFormulation
Formulation
of
site IDF Curve
at-Site&IDF &
UNGAUGED
SITE
Ungauged Site
T7
T7
T8
T8
T9
Part 1 : HP1 (2010) -3/3
Total Nos. of Raingauges
Kauto
188
Dauto
Rauto
627
Pauto
Tauto
Aauto
Cauto
Bauto
Wauto
Nauto
Jauto
Mauto
1000.0
Rainfall Intensity Duration Frequency Curve
Site 3117070@Pusat Penyelidikan JPS Ampang, Selangor
Rainfall Intensity (mm/hr)
100.0
I
10.0
66.8094T 0.1481
100
50
20
10
5
2
d  0.1559
Duration
(hr)
0.25
0.5
1
3
6
12
24
48
72
0.8372
2
155.1
103.8
64.6
27.9
15.9
9.0
5.1
2.8
2.0
5
177.7
118.9
74.0
31.9
18.2
10.3
5.8
3.3
2.3
Yearly Return Period
10
20
196.9
218.2
131.8
146.0
82.0
90.8
35.4
39.2
20.2
22.4
11.4
12.7
6.4
7.1
3.6
4.0
2.6
2.9
50
249.9
167.2
104.1
44.9
25.7
14.5
8.2
4.6
3.3
100
276.9
185.3
115.3
49.7
28.4
16.1
9.0
5.1
3.6
1.0
0.1
1
Duration (hr)
10
100
 Part 1 : HP1 (2010)
 Part 2 : NAHRIM Tech. Guide No.1
 Chap. 1 – 1.2 (problem state. &
1.3 (objective)
 Chap. 2 – Approach & Methodology
 Chap. 3 – Results & Findings
 Part 3 : Chap. 4 - Worked Example
Part 2 : NAHRIM Tech. Guide No.1
1.1 Background: Climate Change Scenario
 A study that has been carried out indicate a possible increase
in inter-annual and intra-seasonal variability with increased
hydrologic extremes (higher high flows and lower low flows)
at various northern watersheds in the future (2025-2050);
 The probability of increase in rainfall would lead to a raise in
river flow of between 11% and 47% for Peninsular Malaysia
with low flow reductions ranging from 31% to 93% for the
central and southern regions (NAHRIM, 2006);
 Parts of Malaysia may experience a decrease in return for
extreme precipitation events and the possibility of more
frequent floods as well as drought
1.2 Problem Statement
HYDROLOGIC & HYDRAULIC DESIGN
To estimate water surface profile, platform level, size of hydraulic
structure corresponding to any return period of occurrence or level of
protection AVERAGE RECURRENCE INTERVAL (RETURN PERIOD)
Sg Guntung
[13.86km
Data units/pixel: Horizontal=8.0days Vertical=0.84mm
Sg Cakah Dua
[11.00km]
Kg Che
Salmah
Kg
Guntung
Luar
Kg K
Guntung
Sg Setiu
[5.48km]
Sg Pancur
Merah
[10.40km]
A
A
710630:0800
8001
8601
9201
9801 YYMM
A
site 5328044 KG. SG. TONG at TERENGGANU Rain mm/day (Total=94149)
Sg Setiu
[8.6km]
Bdr
Permaisuri
Sg Pelung
[9.3km]
Sg Setiu
[11.11km]
Data units/pixel: Horizontal=5.00days Vertical=0.021m
Start Time: 710630 080000
Finish Time: 1050131 090000
Lower Value:
Upper Value:
0.0
410.0
Sg Ima Putih
[12.38km]
Sg Tarum
[7.97km]
Kg
Seladang
Sg Setiu
[14.55km]
Sg Lirim
[8.70km]
A
A
810920:123001 8701
9001
9301
9601
9901
A
site 5229436 SG. NERUS at KG. BUKIT,TERENGGANU Stage m
Start Time: 810920 123001
Finish Time: 1040427 123700
Lower Value:
Upper Value:
Sg Tarum
[8.7km]
Sg Lirim
[13.16km]
Sg Setiu
[9.48km]
0201 YYYMM
Sg Setiu
[4.34km]
Sg Tarum
9.5km]
6.00
16.00
HYDROLOGY
MODELING
HYDROMETEOROLOGY
DATA
HYDRAULIC
MODELING
WATERSHED –
“MEDIUM SYSTEM”
HYDRAULIC
STRUCTURES
1.3 Objective of Technical Guideline
 To assist engineers, hydrologists and decision
makers in designing, planning and developing
water-related infrastructure under changing
climatic conditions.
 To introduce an approach of quantifying the
scale of climatic change to surface water
systems.


The main purpose of this guideline is to derive climate
change factor (CCF)
CCF – defined as the ratio of the design rainfall for each
of the future periods (time horizons) to the control
periods of historical rainfall)
Chap. 2: Approach & Methodology
Part 1
IDF
formulation
Obtain observed annual
maximum rainfall over
various durations
STEP 1:
Obtain downscaled climate data
projection
Part 2
Derivation of
CCF
Review, update &
reformulate IDF
relationships
(1970 – 2007)
STEP 2:
Bias correction of downscaled
data
Statistical Downscaling
Model: 18 GCMs
(2046-2065)
STEP 3:
Derivation of CCF
Dynamic Downscaling
Model: RegHCM-PM
(2025-2034, 2041-2050)
STEP 4:
Disaggregation of 1-day design
rainfall to short duration and
reformulation of IDF Curves
STEP 5:
Rainfall-runoff modelling:
Obtain future Qp
2.3.2 - Derivation
of Climate Change
Factor (Pg.13)
defined as a ratio of
the design rainfall
for each of the
future periods to
the control periods
(historical) for each
time horizon.





Eq. 28 (Pg.17)
STEP 1:
Work out current (1971-2007) return levels of all
rainfall events with return periods between 2 and
200-years from observed database rainfall data using
GEV and EV1.
STEP 2:
Identify current return levels for 7 return periods (1 in
5, 10, 20, 25, 50, 100 and 200-year events) from STEP
1.
STEP 3:
Repeat STEP 1 using climate model data for the period
1981-2000 and 1984-1993 (control period) from the
18 GCMs and RegHCM-PM respectively.
STEP 4:
Repeat STEP 3 using climate model data for the
periods 2025-2050 (RegHCM-PM) & 2046-2065
(GCMs)
STEP 5:
Calculate climate change load factors by dividing the
return level for each of the future periods (STEP 4) by
the return level for the control period (STEP 3), again
for all of the return periods.
2.4 Incorporation of CCF and
Historical at-Site IDF (Pg.14)
2.4.1
&
2.4.2
2.4.3
Eq. 30 (Pg.17)
Eq. 29 (Pg.17)
Chap. 3: Results & Findings
Table 3.1: At site 1 day Climate Change Factor
(CCF) corresponding to Return Period in
Peninsular Malaysia (Pg. 20-23)
Climate Change Factor, CCF
State
Kedah
No.
Station ID
Station Name
Return Period, T
2
5
10
20
25
50
100
200
1
6207032
Ampang Pedu
1.05
1.08
1.09
1.10
1.11
1.12
1.13
1.13
2
5507076
Bt.27, Jln Baling
1.12
1.16
1.18
1.20
1.21
1.22
1.24
1.25
3
5808001
Bt.61, Jln Baling
1.08
1.13
1.16
1.18
1.19
1.21
1.22
1.24
4
5704055
Kedah Peak
1.14
1.20
1.24
1.26
1.27
1.29
1.31
1.33
5
5806066
Klinik Jeniang
1.15
1.17
1.18
1.19
1.20
1.20
1.21
1.22
6
6108001
Komp. Rmh Muda
1.15
1.24
1.29
1.33
1.34
1.38
1.41
1.44
7
6206035
Kuala Nerang
0.97
1.07
1.13
1.17
1.18
1.22
1.25
1.28
8
6306031
Padang Sanai
1.08
1.09
1.11
1.14
1.15
1.18
1.23
1.28
9
6103047
JPS Alor Setar
1.07
1.17
1.22
1.26
1.28
1.32
1.35
1.38
Table 3.2: At site 1-day Future IDF Parameter
(λ’) corresponding to Return Period in
Peninsular Malaysia (Pg. 23-26)
1-day λ'
State
Kedah
No.
Station ID
Station Name
Return Period, T
2
5
10
20
25
50
100
200
1
6207032
Ampang Pedu
69.47
71.27
72.22
73.00
73.22
73.86
74.41
74.90
2
5507076
Bt.27, Jln Baling
58.55
60.64
61.84
62.86
63.16
64.04
64.84
65.56
3
5808001
Bt.61, Jln Baling
51.41
53.74
55.00
56.06
56.37
57.24
58.02
58.71
4
5704055
Kedah Peak
92.90
98.19
100.91
103.08
103.70
105.44
106.93
108.24
5
5806066
Klinik Jeniang
68.59
69.98
70.71
71.30
71.47
71.95
72.37
72.73
6
6108001
Komp Rmh Muda
60.25
64.83
67.41
69.61
70.27
72.14
73.83
75.37
7
6206035
Kuala Nerang
53.34
58.78
61.68
64.07
64.76
66.71
68.42
69.94
8
6306031
Padang Sanai
65.37
65.71
66.84
68.48
69.10
71.32
73.94
76.97
9
6103047
JPS Alor Setar
69.44
75.61
79.04
81.94
82.79
85.23
87.41
89.38
IDF Parameters – Baseline (Historical) & Future
State
Kedah
Station ID
Station Name
Derived Parameters
λ
λ'
κ
θ
η
5507076
Bt. 27, Jalan Baling
52.40
64.84
0.172
0.104
0.788
5704055
Kedah Peak
81.58
106.93
0.200
0.437
0.719
5806066
Klinik Jeniang
59.79
72.37
0.165
0.203
0.791
5808001
Bt. 61, Jalan Baling
47.50
58.02
0.183
0.079
0.752
6103047
Setor JPS Alor Setar
64.83
87.41
0.168
0.346
0.800
6108001
Kompleks Rumah Muda
52.34
73.83
0.173
0.120
0.792
6206035
Kuala Nerang
54.85
68.42
0.174
0.250
0.810
6207032
Ampang Padu
66.10
74.41
0.177
0.284
0.842
6306031
Padang Sanai
60.33
73.94
0.193
0.249
0.829
3.3 1 Day Climate Change Factor
For Ungauged Sites (Pg. 27)
Fig. 3.1 – 3.8
(Pg. 28-32)
Figure 3.1: 1 Day Climate Change Factor (CCF) – 2yrs ARI
Figure 3.2: 1 Day Climate Change Factor (CCF) – 5yrs ARI
Figure 3.3: 1 Day Climate Change Factor (CCF) – 10yrs ARI
Figure 3.4: 1 Day Climate Change Factor (CCF) – 20yrs ARI
Figure 3.5: 1 Day Climate Change Factor (CCF) – 25yrs ARI
Figure 3.6: 1 Day Climate Change Factor (CCF) – 50yrs ARI
Figure 3.7: 1 Day Climate Change Factor (CCF) – 100yrs ARI
Figure 3.8: 1 Day Climate Change Factor (CCF) – 200yrs ARI
3.4
LIMITATIONS OF GUIDELINE
The climate projection data used in the calculation of climate change factor
in this study are averaged from 18 chosen GCMs. For this study, the emission
scenario A1B from IPCC SRES is assumed. The A1B is a scenario in which the
usage of all energy sources is evenly balanced. The dataset used in this
analysis covers only two future periods from 2025 to 2050 and from 2046 to
2065. The climate change factors, CCF and modified λ, λ’ in this guideline are
calculated for 1 day (24 hours) rainfall duration only.
 Part 1 : HP1 (2010)
 Part 2 : NAHRIM Tech. Guide No.1
 Chap. 1 – 1.2 (problem state. &
1.3 (objective)
 Chap. 2 – Approach & Methodology
 Chap. 3 – Results & Findings
 Part 3 : Chap. 4 - Worked Example
Chap. 4 –
Worked
Example
(Pg.37-52)
Example 6:
DESIGNED FLOOD PEAKS – SG KEDAH
Peak Discharges (Qp)
100-years ARI
Item
Climate
Time Change
Horizon Factor
(CCF)
1-Day
Design
Rainfall
(mm)
Percentage
Climate
Climate
Increase of
Change
Change
Flood
Scenario
Scenario
Magnitude
Flood
Flood
(%)
Magnitude
Magnitude,
Increment
Qp (m3/s)
(m3/s)
Baseline
-
-
241
2048
-
-
1
2020
1.05
245
2111
63
3.1
2
2030
1.09
257
2268
220
10.7
3
2040
1.14
268
2430
382
18.7
4
2050
1.19
280
2602
554
27.1
5
2060
1.25
293
2785
737
36.0
2.50
1.50
2.00
1.40
Increment rate
of flow
737m3/s [598.1]
1.50
1.30
554m3/s [449.5]
1.00
1.20
382m3/s[310.5]
0.50
1.10
Increment rate
of rainfall
220m3/s [179]
0.00
2020
2025
2030
2035
2040
2045
2050
Projection Year (2020 -2070)
2055
2060
2065
1.00
2070
Climate Change Factor
Relative Temperature (°C)
Projected Daily Annual Mean Surface Temperature for Malaysia
& Climate Change Factor of Sungai Kedah
ANALYSIS OUTCOME: WATER RESOURCES SECTOR
FLOOD MAPS– SG KEDAH
Time
horizon
Area for flood depth (km2)
0.01 0.5 >1.2 m
Sum
0.5 m
1.2 m
Baseline
50.50
41.55
35.57
127.62
2020
51.24
43.91
37.92
133.06
2030
51.01
45.18
39.90
136.10
2040
50.51
46.86
42.00
139.36
2050
49.13
49.17
44.20
142.50
2060
48.16
50.00
46.95
145.10
terima kasih
TECH GUIDE No.2 –
The Design Guide for
Rainwater Harvesting
System
25 Feb. 2014