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Municipal Corporation of
Greater Mumbai, India
“Managing Mithi Drainage Basin
To Enhance Flood
Resiliency”
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Mumbai Topography and Drainage
� Merger of 7 islands in Island City, 4
islands in Suburban District.
� Surrounded by water on three sides.
� Much of the area is close to sea level.
� Gravity drainage system affected by
high/low tides.
� During high tide ingress of sea water.
� Island City has no natural drainage
outlet.
� Mithi largest river flowing in Suburban
District
� Catchment area 7265 hectares
� Length approx. 17.9 km
� Storm Water Drainage Network is
more than 150 years old designed for
rainfall of 25 mm per hour and run off
co-efficient of 0.5.
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� Rainfall Characteristics
� Watershed degradation
� Inadequate Storm Water
Drainage System
� Increase in Impermeable
Surface Cover
944 mm in 24 hrs.944 mm in 24 hrs.On 26On 26thth July 2005July 2005
Vulnerability of MUMBAI
To Flooding
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Urbanisation has increased vulnerability of
Mumbai to floods
� Narrowing of banks for housing and slums
� Reclamation of river beds by industrial units
� Diversion of course of the river for construction of the
airport
� Main river has been forced to turn 900 four times in
quick succession.
� Some sections are bunded with walls and
embankments on both sides.
� Reclamation of natural ponds
� Reclamation of mangroves for construction of Bandra –
Kurla complex.
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Moraraji Nagar Slum EncroachmentMoraraji Nagar Slum Encroachment
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Mithi on Kurla Mithi on Kurla –– Saki Naka RoadSaki Naka Road
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Land use changes have increased
vulnerability of Mumbai to floods
Change in land use pattern has led to an increase in
run off coefficient to almost 1.0
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Mithi River Flooding Mithi River Flooding –– 2626thth July 2005July 2005
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Recommendation: Do not obstruct water flow of the
river
Initiatives taken since 2006
�Widening & deepening of Mithi River is almost completed
�940,406 cubic meters of silt and 492,000 cubic meters of hard rock
has been excavated from the river bed till 31st March 2011
�Construction of R.C.C. retaining wall of 7.8 km length on both the
banks along with 6 to 12 mtr wide service roads.
�Two weirs have been completed along the river.
�4922 (residential & non residential) structures have been
demolished for widening the river, 663 structures remain to be
demolished
�Expenditure incurred till 31st March 2011 – 69.8 Million Euros
�Expected expenditure to complete the remaining work – approx 71
Million Euros
�Target date of completion – December 2012
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SAKINAKASAKINAKA
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Weir Wall at BamandayaWeir Wall at Bamandaya
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New Bridge At Kranti Nagar
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Upstream of Kranti Nagar Bridge
Before
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Upstream of Kranti Nagar Bridge
After
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BEFORE
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AFTER
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Recommendation: Develop Early Warning Systems
� Installation of 35 automatic
weather stations at 28 locations
� Console gives audible alarm
when the rainfall exceeds 10mm
in 15 minutes
� Rainfall data is transmitted every
15 minutes to the EOC, MCGM
� Flow Gauges have been installed
upstream of Mithi River and a
measuring scale has been marked
on the existing pier of
Krantinagar Bridge to indicate the
level of water in the Mithi river
and issue warning to the
population living downstream20
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KRANTINAGAR
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FLOODING SPOTS
CATCHMENT
BOUNDRY
IRLA PUMPING
IRLA NALLA
IRLA NALLA Br-A
IRLA NALLA Br-BGARWARE NALLA
IRLA NALLA Br-C
Recommendation: Augment the capacity of the storm water drainage system to cater to the increase in runoff
ABHISHEK NALLA
Nalla training work
completed Work under SRA
development
FLOODING SPOTS
1 Milan Subway
2 VM Road
3 Near Cooper Hospital
4 JVPD Area
5 Near Vile Parle Station
6 Sahar Road Junction
1
2
3
4
5
6
Work of training yet to
start (funded by
MCGM)
Work of training under
progress
Existing Trained
KOLE DUNGARI NALLA
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Pumping Stations
Storm Water Pumping Station at Irla
Capacity – 48 Cubic Meter / Second
No. of Pumps – 8
Capacity of each pump – 6 Cubic Meter / Second
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Progress … Inlet channel - Irla
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Progress … Irla
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Recommendation: Prepare detailed Contour Maps to
identify the sub-catchment and low lying areas
A contour map of Mumbai with 0.2 m interval has been
completed
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Recommendations
� Conserve wet lands
The reclamation of mangroves
for construction of the
Bandra Kurla complex has
increased the likelihood of
flooding.
� Promote recreational
activities along the banks
of the river
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GOALS OF DRMMP
Recommendation: Preparation of a comprehensive
Disaster Risk Management Master Plan
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Policy Recommendations
�Make flood risk and flood hazard
assessments an integral part of the
master planning process
�Record construction details along with
the plinth and ground level in a master
inventory
�Provide flood-resistant temporary
shelters
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Municipal Corporation Of Greater Mumbai
Thank You
Making Mumbai a better and safe place to live in…
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