flood resilience study for mithi river catchment in mumbai ... · 2. mike 11 used for flood...
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Vinay Nikam and Kapil Gupta
IIT Bombay , Mumbai, India
Flood Resilience Study for Mithi River Catchment in Mumbai, India
International Conference on Flood Resilience Experiences in Asia and Europe 5-7 September 2013
Exeter, UK
Objectives of the study
• To carry out a flood damage assessment in the Mithi River
catchment and suggest resilience measures
•Scenarios considered
1. Three rainfall return periods I. 1 in 1 year II. 1 in 10 years III. 1 in 100 years
AND 1. Climate change
a. Business as usual b. Uplift factor of 1.20 applied to rainfall
Description of the Mithi catchment
• Catchment area- 7,295 Ha
• Length of river - 17.84 km • Annual average rainfall 2430
mm (Santa Cruz) • 95% falls during the monsoon
months from June to September
• 70 % of this rainfall occurs in
July and August • 50 % of this occurs in just 2-3
events
Mumbai
MithiRiver
Mumbai
Mithi River catchment (study area)
India
MithiRiver
Mumbai
Mithi River catchment (study area)
Mumbai
Mithi River profile
(Government of Maharashtra, 2006)
Flood history and mitigation measures
• 26 July 2005, major flood due to 944 mm rainfall in 24 hours-
60% city submerged, transport paralyzed, over 500 dead
• Mitigation measures undertaken by Municipal Corporation
1. Installation of real time rainfall alert system in 2006
2. Restoration and widening of Mithi River
3. Construction of holding pond/weir
4. Construction of flood protection walls for first 7.80 km
5. Retaining wall for the remaining (approx 8.0 km) length of river
in progress
Methodology
1. Population forecast provided by planning authorities
2. MIKE 11 used for flood simulation and water levels computed
for the three rainfall scenarios
3. Flood spread and depth
4. Depth damage curves
5. Vulnerability map
6. Flood damage return period curve
Combined scenarios for the Mumbai
Optimistic
Pessimistic
BAU
Population forecast
Optimistic
Pessimistic
BAU
Rainfall scenario
1 in 10 years
1 in 100 years
1 in 1 year
Climate change
uplift factor
1.20
BAU
Adaptive capacity
Adpatation 2
Adpatation 3
Adaptation 1
0
2
4
6
8
10
12
14
16
18
1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001 2011 2021 2031
Po
pu
lati
on
(m
)
Year
Pessimestic BAU Optimistic
BAU
Pessimistic
Optimistic
Population forecast
12
13
14
15
16
17
2001 2011 2021 2031
Po
pu
lati
on
(m
)
Year Pessimestic BAU Optimistic
Pessimistic
Optimistic
BAU
Slum population scenarios
0
1
2
3
4
5
6
7
8
1981 1986 1991 1996 2001 2006 2011 2016 2021 2026 2031
Slu
m p
op
ula
tio
n (
m)
Year
Optimistic BAU Pessimistic
BAU
Pessimistic
Optimistic
Under pessimistic scenario, population is considered to remain steady after 2021 because most of the low-lying areas are already habitated by slums and saturated. Under optimistic scenario, slum population has been considered to be reduced to 39.5 % and 28.0 % for year 2021 and 2031 respectively
Rainfall intensities
Rainfall intensity (mm/h)
Return periods
Scenario 1 10 100
Business as usual (BAU) (Govt of Maharashtra,2006)
30 66 93
Uplift factor of 1.20 36 79 111
Mithi River in MIKE 11
Water level in river for 3 scenarios
0
5
10
15
20
25
30
1500 3500 5500 7500 9500 11500 13500 15500 17500
Le
ve
l (m
)
Chainage (m)
Bed level
111 mm/h (1 in 100 yr, uplift factor=1.20)
79 mm/h (1 in 10 yr, uplift factor=1.20)
36mm/h (1 in 1 yr, uplift factor=1.20)
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 100 yr I = 111 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 10 yr I = 76mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 1 yr I = 36 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 100 yr I = 111 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 10 yr I = 76mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 1 yr I = 36 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 100 yr I = 111 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 10 yr I = 76mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 1 yr I = 36 mm/h
Flood spread and inundation (T=1 year)
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 100 yr I = 111 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 10 yr I = 76mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 1 yr I = 36 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 100 yr I = 111 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 10 yr I = 76mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 1 yr I = 36 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 100 yr I = 111 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 10 yr I = 76mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 1 yr I = 36 mm/h
Flood spread and inundation (T=10 years)
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 100 yr I = 111 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 10 yr I = 76mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 1 yr I = 36 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 100 yr I = 111 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 10 yr I = 76mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 1 yr I = 36 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 100 yr I = 111 mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 10 yr I = 76mm/h
15-30 cm
30-60 cm
60-90 cm
90-120 cm
120-150 cm
Depth
T= 1 in 1 yr I = 36 mm/h
Flood spread and inundation (T=100 years)
Depth damage curves
Depth-damage curves
Land use map developed from
- field surveys
- interviews
Slum area
Building area
Mithi River
Depth damage curves
0.00
0.30
0.60
0.90
1.20
1.50
1.80
2.10
2.40
2.70
3.00
3.30
0 500 1000 1500 2000 2500
Dep
th (m
)
Damage (Rs. per sq.m.)
Slum at ground Slum with elevated plinth levels
Building at ground level Building with elevated plinth
50 INR/m2
200 INR/m2
250 INR/m2
500 INR/m2
Vulnerability
T= 1 in 100 yr I = 111 mm/h
50 INR/m2
200 INR/m2
250 INR/m2
500 INR/m2
Vulnerability
T= 1 in 10 yr I = 76mm/h
50 INR/m2
200 INR/m2
250 INR/m2
500 INR/m2
Vulnerability
T= 1 in 1 yr I = 36 mm/h
Vulnerability map (T=1 year)
50 INR/m2
200 INR/m2
250 INR/m2
500 INR/m2
Vulnerability
T= 1 in 100 yr I = 111 mm/h
50 INR/m2
200 INR/m2
250 INR/m2
500 INR/m2
Vulnerability
T= 1 in 10 yr I = 76mm/h
50 INR/m2
200 INR/m2
250 INR/m2
500 INR/m2
Vulnerability
T= 1 in 1 yr I = 36 mm/h
Vulnerability map (T=10 years)
50 INR/m2
200 INR/m2
250 INR/m2
500 INR/m2
Vulnerability
T= 1 in 100 yr I = 111 mm/h
50 INR/m2
200 INR/m2
250 INR/m2
500 INR/m2
Vulnerability
T= 1 in 10 yr I = 76mm/h
50 INR/m2
200 INR/m2
250 INR/m2
500 INR/m2
Vulnerability
T= 1 in 1 yr I = 36 mm/h
Vulnerability map (T=100 year)
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 100 yr I = 111 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 10 yr I = 76mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 1 yr I = 36 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 100 yr I = 111 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 10 yr I = 76mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 1 yr I = 36 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 100 yr I = 111 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 10 yr I = 76mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 1 yr I = 36 mm/h
Flood damage (T=1 year)
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 100 yr I = 111 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 10 yr I = 76mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 1 yr I = 36 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 100 yr I = 111 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 10 yr I = 76mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 1 yr I = 36 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 100 yr I = 111 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 10 yr I = 76mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 1 yr I = 36 mm/h
Flood damage (T=10 years)
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 100 yr I = 111 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 10 yr I = 76mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 1 yr I = 36 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 100 yr I = 111 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 10 yr I = 76mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 1 yr I = 36 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 100 yr I = 111 mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 10 yr I = 76mm/h
< 1 m INR
1 – 2 m INR
2 – 3 m INR
3 – 4 m INR
4 – 5 m INR
5 – 6 m INR
Damage
6 – 7 m INR
7 – 8 m INR
8 – 9 m INR
11 – 12 m INR
9 – 10 m INR
10 – 11 m INR
T= 1 in 1 yr I = 36 mm/h
Flood damage (T=100 years)
Damage – Return period curve
0.76
10.75
32.57
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
0 10 20 30 40 50 60 70 80 90 100
Dam
age
(M
IN
R)
Return period (year)
Summary and Conclusions
1. Flood simulation for present and future rainfall
intensities has been carried out
2. Flood impact assessment has been carried out
3. The depth-damage curves have been developed
4. Damage assessment has been carried out
Results
Study has resulted in identification of most severe flood
prone areas and expected damages
This will help in
1. Prioritising rescue and relief measures
2. Planning future mitigations measures
Future measures required
Need to setup flow gauges at various critical locations
and issue flood warnings based on real-time flood
forecast mechanism
Acknowledgements
• Research on the CORFU (Collaborative research on flood resilience in urban areas) project was funded by the European Commission through Framework Programme 7, Grant Number 244047
CORFU Mumbai Workshop (4-5 Feb, 2011)
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