Techniques for flood hazard zonation and vulnerability ... - NDMA

3/17/2010
5-Day Training Workshop
On
“Flood Mitigation”
Title:
On:
At:
Organized By:
Flood Hazard Vulnerability and
Mapping Techniques
February 16, 2010
Islamabad
NDMA-UNDP
Sequence of Lecture
• Pakistan - River System;
• Flood Hazard Zonation and Vulnerability Techniques -
Objectives;
• Tools/Techniques used for Flood Hazard Zonation and
Vulnerability Mapping in Pakistan;
• Steps In Flood Risk/Vulnerability Mapping.
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3/17/2010
INDUS RIVER SYSTEM
Objectives of Flood Hazard Zonation and Vulnerability
Mapping Techniques Used in Pakistan
This is done for achieving the following objectives:
• To identify the severity of flood hazard and vulnerability
of certain area for necessary flood planning ;
• To ensure that measures adopted for flood hazard and
vulnerability management are sufficient;
• To ensure a balance between flood preparedness and
measures
taken for
flood hazard & vulnerability
reduction;
• Assessment of available capacities that may facilitate in
flood risk management.
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3/17/2010
Tools/Techniques Used for Flood Hazard Zonation
and
Vulnerability Mapping
• Meteorological data;
• Flood Frequency Analysis;
• Hydrological Data;
• Past /Historical Flood Damages Record;
• Flood Plain Maps;
• Bathymetric Surveys;
• Flood Forecasting Computer Model;
• Comprehensive Flood Management Plans;
• Flood Warning Manual;
• Telemetry System;
• Standard Operating Procedures for Dams;
• Weather Radars.
Tools/Techniques Used for Flood Hazard Zonation
and
Vulnerability Mapping
• Meteorological data:
Rainfall data collected for the past years (62
years) is used to make an
analysis/estimate
of any
likely
flooding
situation
on any
river
system/river catchment/urban area based on which future planning
towards flood control/land-use
etc. can be made. This data is collected
from various rainfall gauges installed in the province and is available
on CD, internet etc. (Used at National, Provincial and District levels).
• Flood Frequency Analysis:
This tool is used for the design of an effective flood management
system (dam/bund/dike/spur etc.) based on aflood
of certain definite
return period (5/10/25/50/100/10001000 years etc.). Certain engineering
techniques (Log Pearson, Log Gumbel etc.) are used for this analysis.
(Used at National, Provincial and District levels).
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3/17/2010
Tools/Techniques Used for Flood Hazard Zonation
and
Vulnerability Mapping
• Hydrological Data:
The success or failure of any Flood Frequency Analysis technique
depends largely on the authenticity of hydrological data and the
correctness of hydrological data is dependent on the measurement
system by virtue of which this data is gathered/recorded. Such data
include: rainfall, runoff, discharge/river flow/stream flow etc. (Used at
both Provincial and District levels).
• Past /Historical Flood Damages Record:
Records
of past
flood
damages due
to floods
in
certain river
system/urban area/hill torrent area help in the planning of future flood
control works/embankments/bunds/spurs/new
infrastructure in
the
cities etc. (Used at National, both Provincial and District levels).
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3/17/2010
HISTORICAL FLOOD DAMAGES
HISTORICAL FLOOD DAMAGES
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3/17/2010
Tools/Techniques Used for Flood Hazard Zonation
and
Vulnerability Mapping
• Flood Plain Maps:
For main
rivers,
Flood Plain
Maps
have
been
prepared based on various categories of floods
(Medium/High/Very
High/Exceptionally High
etc.)
based on which, owing to a particular flood category,
inundation levels are assessed for the existing and
the new planned infrastructure activity/flood control
facility/cropping activity
etc.
(Used
at
National,
Provincial and District levels).
INDUS RIVER SYSTEM – Flood Risk Map
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3/17/2010
INDUS RIVER SYSTEM - Flood Risk Map
Tools/Techniques Used for Flood Hazard Zonation
and
Vulnerability Mapping
• Bathymetric Surveys:
Every year during the monsoon season, river discharges increase on
one hand and at the same time lot of debris, sediment and silt is
brought which
results
in accretion/degradation
of
river
profile.
Bathymetric surveys carried out across the flow of river help in
understanding changed river cross-sectionalsectional profile and hence in
better forecasting of flows. (Used at National, Provincial and District
levels).
• Flood Forecasting Computer Model:
Anticipated flood
events
are
assessed through
FEWS
(Flood
Forecasting Early Warning System) Computer Model which helps not
only in instant flood forecasting but also in future estimate of floods
both at the provincial as well as at the district level. (Used at National ,
Provincial and District levels).
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3/17/2010
Tools/Techniques Used for Flood Hazard Zonation
and
Vulnerability Mapping
• Comprehensive Flood Management Plans:
For flood hazard risk assessment and management
at National,
Provincial
and District
levels
comprehensive
flood management
plans
are
prepared p for a period of 10 years. Based on flood
risk assessment, these plans are implemented in a
phased manner to avert future flood threats. (Used at
National, Provincial and District levels).
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3/17/2010
Tools/Techniques Used for Flood Hazard Zonation
and
Vulnerability Mapping
• Flood Warning Manual:
Flood Warning Manual is used primarily in conjunction with flood plain
maps. Its usage at present is limited. It helps in assessment of
vulnerability of areas which may get inundated in the event of flood of
a certain category and also helps in future planning purposes.
• Telemetry System:
A good flood telemetry system exists at the National and Provincial
level which assists in timely collection and dissemination of rainfall
and river flow data which is used as a planning tool for future
designing and implementation of flood infrastructure (dams/bunds
etc.) besides rural and urban planning.
FLOOD FORECASTING DIVISION,(FFD), LAHORE
( H.F.RADIO NETWORK)
TARBELA
MANGLA
Besham, Jaglot
Skardu, Daggar
Phulra, Oghi
Shinkiari, Khairabad
Nowshera
CHASMA
Kallar, G.H.Ullah
Muzaffarabad, Domel
Kotli, Kohala
Plandri, Azadpatan
W.R.M.D.
SUNNY VIEW LAHORE
FLOOD FORECASTING DIVISION
LAHORE
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3/17/2010
Tools/Techniques Used for Flood Hazard Zonation
and
Vulnerability Mapping
• Standard Operating Procedures For Dams:
For Mangla Dam on River Jhelum in order to cater for Category-I,
II and
III floods, Standard Operating Procedures have been devised for
effective Dam Operation during floods specifically for the purpose of
safety of dam and downstream areas. (Used at National, Provincial and
District levels). Similar arrangements exist for Tarbela Dam.
• Weather Radars:
The existing weather radars at Lahore, Sialkot, Mangla, Rahim Yar
Khan, D.I.Khan,
Karachi and Islamabad are used to assess the weather
condition and based on cloud moisture content, anticipated flood
situation is forecasted which helps in timely pre-emptiveemptive measures.
(Used for both Provincial and District levels).
Weather Radar Network
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3/17/2010
Steps In Flood Hazard Zonation
and
Vulnerability Mapping
• Availability of rain/river-flow/runoff i / ff measurement system
and relevant data;
• Land-use/River surveys;
• Flood Frequency Analysis;
• Flood Hazard/Vulnerability Maps
Departments That Can Assist In Flood Hazard
Zonation and Vulnerability Mapping
• Provincial Irrigation Department;
• Federal Flood Commission;
• National Engineering Services of Pakistan;
• SUPARCO
• Flood Management Experts
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3/17/2010
End of Presentation
Thank You
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