UNIVERSITY OF CENTRAL PUNJAB, FAISALABAD
Project Appraisal and
Financing
Topic: Flood Risk Management
Submitted by:
Saira Khalid (Reg. No. 0201)
Sana Riaz
(Reg. No. 0185)
Sabahat Riaz (Reg. No. 0213)
Umaira Iqbal (Reg. No. 0026)
Section: M.Com 1A
Submitted to:
Sir Nauman Nazir
Date of submission:
28th-May-2014
IMPORTANCE OF FLOOD RISK MANAGEMENT IN PAKISTAN:
Floods are among the most destructive natural hazards causing extensive Damage to the built and
natural environment, and devastation to human settlements. Economic losses due to the effects of
damaging floods have increased significantly around the world. The Asian region experiences
frequent flood disasters of high magnitude, and although the number of deaths caused by
flooding has decreased, the number of affected populations and economic losses have increased
significantly. These trends trigger a need to pay greater attention to the impact of flood hazards
on human development.
PAST HISTORY OF FLOODS IN PAKISTAN:
Pakistan also has long history of floods. In the past 60 years the country has faced 19 major flood
events resulting into loss of 10,668 precious human lives, cumulative flooding of over 594,700
sq km area with 166,075 villages affected and total direct cumulative losses to the tune of about
US $ 30 billion. Floods in Pakistan are generally caused by the heavy concentrated rainfall
during the monsoon season, which are sometimes augmented by snowmelt flows in rivers.
Occasionally destructive floods are also caused due to monsoon currents originally from the Bay
of Bengal (India) and resultant depressions which often result in heavy downpour in the
Himalayan foothills, which is sometime further augmented by the weather systems from the
Arabian Sea (Seasonal Low) and from the Mediterranean Sea (Westerly wave). The monsoonal
runoff discharging in the rivers is further augmented by the water received from melting of snow
from higher reaches upstream of Tarbela Dam in northern Pakistan. Isolated and distributed flash
flood events also occur in Pakistan. From 2005 onwards these have become a regular visitor
during the monsoon season. Also urban floods which occur in the major cities of Pakistan
including Islamabad, Rawalpindi, Peshawar, Lahore, Karachi, Faisalabad, Hyderabad etc. are
also common in the monsoon season. Coastal floods in the southern provinces of Sindh &
Balochistan occur when tropcial storms make landfall in the coastal areas of the country. The
Makran coast and south eastern parts of Sindh bear the brunt of such floods. The most recent of
such events occurred in 2007 (Yemyin cyclone) and in 2010 (Phet cyclone). The most worst and
destructive flood Pakistan has faced were in 2010 which caused record destruction in the history
of Pakistan including loss of 1985 lives. Floods of 2010 and 2011 have also manifested and
strengthened the sea level rise estimates thus have further compounded the flood vulnerability.
REASONS OF FLOODS IN PAKISTAN:
The Indus River is the lifeline of Pakistan. Without the Indus and its tributaries, the land would
have turned into a barren desert long ago. It runs generally south-westward the entire length of
Pakistan, about 2,900 km (1,800 mi), and empties into the Arabian Sea. The Indus and its
tributaries provide water to two-thirds of Pakistan. The principal tributaries of the Indus are the
Sutlej, Beas, Chenab, Ravi, and Jhelum rivers.
OBJECTIVE:
The main emphasis would be at effective flood risk management measures to reduce flood
damages.
The following trends are noticed, pointing up the importance of flood protection in flood
affected areas:
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
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
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Increase in potential damage
Increasing economic value in consequence of changes in land use
Increase in number of extreme flood events
Increasing discharge because of river training or climate changes
Present concepts of integrated flood risk management and the important issues,
considerations and limitations faced when implementing risk reduction activities and
actions.
Serve as a guide, reference and resource on current good practices in flood risk
management in Asia.
Advocate and provide options for considering an integrated flood risk management
approach.
Provide a process driven approach to each component of flood risk management as part
of an integrated disaster risk management cycle.
Contribute to current trends
RISK MANAGEMENT:
We have to make the decisions for controlling the risk. The decision making can be more related
political and administrative aspect. Technical knowledge for decision making is required. Risk
related to flood can be managed by two alternatives:
Risk Monitoring
In this a periodic analysis if actual risk is made. Moreover, during the monitoring
process, the change in type of risk can occur or we may need to conduct more
studies for this purpose. It more studies is not needed then one alternative among
various alternative is selected to implement the plan.
Risk Mitigation
It is the addition to risk monitoring. Means we first have to carry monitoring then
carry mitigation process if needed. It may be needed for more studies or
information required for assessment of risk. The process is repeated if more
alternatives are needed to discover. When completed, the selection of alternative
is done to implement the plan.
Common Steps For Both:
 Risk Assessment
 In this step two things will be included:
 Anticipate the hazards and its identification
 Analysis of hazards
 Consequence analysis (includes economic, social, environmental factors)
 Determine the acceptable level of risk
 What type of uncertainties can occur
 Risk evaluation
 Evaluation of perceived risk
 Evaluation of accepted risk
RISK ASSESSMENT:
Risk assessment can be done for the following important reason:





Due to disasters by flood
Affecting lives of resident
Economic loss
Change in overall climate of earth
Increase in no. of extreme events
Assessment of risk can be done by RISK MAPS which will help the residents and team to assess the
possibility of risk in certain time period and in specific areas. It is a medium of communication to
residents.
RISK IDENTIFICATION:
Risk can be identified through Source-Pathway -Receptor-Consequence model. Risk can be
identified through this process:
•E.g. excess
rainfall
Source
Pathway
•accumualte
water in near by
areas
•water entered in
the city, homes
and building
Receptor
Consequence
•damage of lives
and wealth
Source:
The sources can be of three types for flood:
1. Blocked or overloaded drainage system
When the rainfall excessively in the areas where no proper facility for drainage is
available and cemented buildings are in increased number, the water will be mixed with
wastage of drains.
2. Groundwater flooding:
Secondly, old houses near chalk and sea shore areas are always at risk if the water
level increases.
3. Flooding from overland flow:
Thirdly, the water drainage systems are weak and are filled, unable to drain more
water out of area.
Pathway:
It provides the details about risk prevailing in certain areas and how dangerous it is to live
in those areas.
Receptor:
Receptor refers to the assets that may be harmed by the flood if the flood occurs. The
buildings, etc. are included here.
Consequence:
It can be of several types like:
•
•
•
quantitatively: monetary value
by category: high, medium, low
or descriptively
SCALE FOR ANALYSIS:
Defining the scale is essential for planning. It helps in decision making for assessment of risk
and mitigation of risk. We have three basic scales for analysis:



Macro scale approach
Mesoscale approach
Microscale approach
Macro scale approach:
The approach in which we consider very large area with least details. We can say that
only the most important details are known.
e.g. International area considered having only the important details
Meso scale approach:
The approach in which the less area as compared to macroscale is covered but sufficient
details more as compared to macroscale is taken.
e.g. region wise study of affected land
Microscale approach:
The scale in which small area as compared to other two approaches is considered. The
complete detailed study can be done.
e.g. a specific area of a city in study
For Pakistan we may use Mesoscale approach because this scale is normally used for
larger catchment areas. For the process of risk assessment single land use types based on digital
geographic data are aggregated to larger, more general one. The corresponding amount of losses
is based on statistical economic values and can be described with the unit €/m². Here, protection
measures do not consider characteristics of single buildings or infrastructure facilities.
RISK ASSESSMENT –PROBABILITY:
Objectives for risk assessment:
Flood risk assessment is done because:
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



We want to be aware of complexities
We want to assess our safety measures
We want to assess the acceptable level of risk
We want to assess the damages that can occur if flood comes
We want to support further decision making
Probability of event:
Probability is the study of the chance that a particular event or series of events will occur.
Typically, the chance of an event or series of events will occur is expressed on a scale from 0
(impossible) to 1 (certainty) or as an equivalent percentage from 0 to 100%.
Using probability, we will make the following assessments about flood occurrence risk:
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Hazard assessment of floods
Extinctions and extinction rates
Error and data analysis including uncertainty and error propagation
Forecasting
Steps for Damage Potential Assessment:
Damage potential assessment is composed of the following steps:




determination of hydrologic parameters (design flood)
hydraulic calculations
determination of flood affected areas
determination of damage potential and expected annual damage
In this, we have two important scenerios that will be useful in first two steps:
1. Hydrological
2. Economic
In hydrological, we will determine the water flow and main areas in which floods came in past.
The study of water stages on earth is made to perfectly calculate probability.
In economic, we will calculate the assets and their value, which can be affected by the flood and
their probability of affecting.
The later, two steps are determined and completed using above requirements to arrive at Annual
damage determination.
RISK ASSESSMENT – CONSEQUENCE:
In this we will determine the loss in the monetary form to the assets of any area due to flood. The
loss is better assessed by the combination of two things:
1. Return rate of risk
2. Consequences
The combination of the above things will show that how many chances are there for the reoccurrence of event in future and when this event re-occurs, then what’s the amount of loss that
can be caused in monetary form. Return rate can be calculated as follows:
Recurrence interval = {(n+1) ÷ m}
n is number of years on record;
m is the number of recorded occurrences of the event being considered
It related to flood events losses For example: Damages to persons, financial losses, loss of
production, damages on cultural values, costs for emergency planning and disaster operation.
To quantify monetary damage of a flood event is necessary that these values can be used in
combination with the return period for risk mapping. The methodology quantifies the damage
potential by using only monetary assessment of direct damage.
Like loss related to:
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persons and animals
buildings and outside facilities (e.g. yard, garden)
fixtures and movable assets
stock value (industry, agriculture, retail)
forest and farm vegetation
infrastructure
The extent of potential damage is considerably affected by:
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


flood plains
water depth
duration of a flood event
type of land use
RISK MAPPING:
Risk mapping helps in sustainable planning. It uses the approach in which consequences of flood
events in monetary values combined with return period as weighting factor.
There are two types of users for risk mapping:


Engineers and administrative staff
General public
APPLICATION:
DATA SOURCE:
Before application, we have to collect the data about different things like, what is the area about
which we are going to collect the data. It is mostly the flooded area but the area of watershed
must also be considered for pre-stages calculation.
The data needed at first involve for pre-processing purposes (runoff modelling & hydraulic
simulation) are:
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
the catchment area and topography,
the river system,
the land use and soil types,
precipitation data and corresponding water levels,
survey data or at least cross sections.
Input parameter:
Two types of calculations are made here,


Hydrological
Economic
Hydrological:
In this type of calculation, detailed information on flow depths and the area-measured extent of
flooding are shown. In this, corresponding water depth caused by a certain flood event and the
possible extent of endangered area is included. No loss calculation is made here.
Economic:
It involves the determination of the asset values for each land type. Data can be obtained from
national, regional or local authorities responsible for spatial planning or statistical survey. Like in
Pakistan, there is “National disaster management authority” and “Ministery of Climate change”
It depends from the size of the catchment area also.
CALCULATION OF MONETARY LOSSES BY FLOODS:
In Pakistan, flood of 2010 caused the monetary loss of $43 billion (estimated).
The value of the asset can be based upon two things:


Cost of construction
Inventory
Gross concept
(Constant value)
at purchase price
Net concept
(depreciation
considered)
Asset value
Gross concept
at actual price
Net concept
Value of
Property
Damaged (Rs
in Million)
Value of
Property
Damaged (Rs in Lives Lost
Million)
Villages
Affected
1950
Unadjusted
199.80
Adjusted
11,282.00
2,190
10,000
1956
155.50
7,356.00
160
11,609
1957
152.50
6,958.00
83
4,498
1973
5,137.00
118,684.00
474
9,719
1976
5,880.00
80,504.00
425
18,390
1978
4,478.00
51,489.00
393
9,199
1988
6,879.00
25,630.00
508
1,000
1992
34,751.00
69,580.00
1,008
13,208
1995
6,125.00
8,698.00
591
6,852
2001
450.00
450.00
219
50
2003
5,175.00
5,175.00
484
4,376
2004
15.00
15.00
85
47
Year
2005
Not Reported
59
1,931
2006
Not Reported
541
2,477
2007
Not Reported
586
6498
2008
Not Reported
157
800
2009
Not Reported
99
89
819,381.00
1961
14,316
2010
819,381.00
RISK EVALUATION:
Damage Functions:
These functions represent the relation between hydraulic parameters (water depth) and damage
(vulnerability). They give information on the amount of damage in percent for different water
depths while considering the respective land use type.
Its characteristics are:

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
first occurrence of damage
maximum damage value
shape of the function
There are two types of stage-damage curves:


one is based on actual damage costs
the other type is based on synthetic costs (used for benefit-cost analyses)
The development of residential synthetic cost stage-damage curves needs the following steps:
1. Representative classes of houses are selected in the area, usually based on building size.
2. A sample of houses is selected in dwelling class. For each room the contents are checked,
values are noted or the height above floor level can also be noted. Preferably, a qualified
quantity surveyor or value should undertake this step.
3. Values are averaged across each sample for each class of house and stage-damage curves
are constructed.
This method does not describes the actual cost but it describes the average damage caused by
flood to houses in a particular area.
Calculation of specific assets:
This could be done using the method of regionalisation. This method to calculate the flood
damage potential is composed of three steps:



determination of asset value per land use type in [€]
identification of corresponding land use areas in[m²]
intersection of statistical-economic data and land use types to calculate the specific asset
value in [€/m²]
Advantages of this method:
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
No time consuming
Based on figures disclosed by govt.
For different land types
Disadvantages:


Does not represent real damage
Only for microscale approach
Method of regionalization:
Regionalization is the process of dividing an area into smaller segments called regions.
This process includes:

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
inundation areas with water depth
land use distribution
specific asset values
damage functions
damage within each grid cell can be calculated as:
DLnij = CLnij * VLn
Where,
jiD, = specific damage for grid cell [i,j] in (€/m²), C percentage of damage in depend-ence of
land use category Ln and the water depth h=Lnj,ii,j in grid cell [i,j] in [%] andLnV = specific asset/capital stock for each land use type Ln in [€/m²].
total damage can be determined as:
= DLnij * No. of houses affected in percentage
Annual damage potential:
as we have discussed earlier that this method does not provide us with exact result. So,
probability is used. The calculation is based on available statistical data and is expressed as
annual flood damage potential. Therefore the damage is weighted by the frequency of returning.
We have to take here assumption that the maximal damage is set as the upper limit of integration
(recurrence interval T¥ = Tmax); the expected damage can only be calculated for events which
probability of occurrence is more frequently than Tmax. The corresponding probability for this
design event is Pmax As consequence the remaining risk can’t be considered.
For solving this equation, it is necessary to calculate the potential damages for flood events of
different estimated probabilities.
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
input data: water depths for each flood event
damage functions
result: damage potential
Total damage potential
Integration of all damage potential values (assuming linear function of damage). Applying this
method the combination of flood probability and monetary damage assessment is managed. The
flood risk can be estimated based on annual flood.
MEASURES:
The science of flood risk management is a strategy, to reduce the damages of floods while
keeping its benefits. It include pre flood, during flood and post flood phases. The pre flood stage
includes planning structure to cope with potential upcoming severe floods.
The studies are conducted on all major rivers to determine the probability of flood occurrence.
This yield the results in terms of 2 to 1000 or 10,000 year return period flood. On the basis of
this statistics of flood discharges, the flood risk zoning maps are prepared which indicate the
potential effected areas by each category flood. This risk maps are supposed to be the public
document, therefore delivered to all potentially affected communities to give them an idea of risk
in the area of their settlement and cropping.
In order to cope with this various category floods, the studies are conducted in planning phase to
determine their impact on strategic assets. There are two different ways to mitigate floods:
1.Structural
2. Non- Structural
1. Structural Measures:
Structural measures are in the nature of physical measures and help in “modifying
the floods
1. Construction of dams:
Construction of protective works such as flood storage reservoirs, diversion of
water to side channel storage or other watersheds, construction of storm channels
to carry water around the area to be protected, and levees along the floodway
provide tools to reduce flood damages. Such works can be constructed to various
levels of protection, usually based on) minimum standards for flood protection ;)
the optimum level of costs and benefits based on an economic to meet established
levels
of
acceptable
risk.
2. Bridges and roads:
Bridges generally constrict the flow of water, and they can act as artificial dams if
debris jams on the structure. In all cases, their hydraulic characteristics must be
considered at the design stage to prevent a UN acceptable rise of water levels
upstream of the structure.
3. Embankments:
Embankments have been extensively used for protection against floods of important
towns and lands. However, the embankments are now the best means of
communication in the flood-prone areas and are being recklessly used for
transportation of materials by tractors and other heavy vehicles. During floods, people
shift to the embankments for temporary shelter and often settle down there for good.
4.
Water Shed Management:
Timely cleaning, de-silting and deepening of natural water reservoir and drainage
channels
(both
urban
and
rural)
must
be
taken
up.
5. Reservoirs:
The entire natural water storage place should be cleaned on a regular basis.
Encroachments on tanks and ponds or natural drainage channel share to be removed
well before the onset of monsoon.
6. Natural water retention Basins:
Construction and protection of all the flood protection embankments, ring bunds and
other bunds. Dams and levees can also be constructed which can be used as
temporarily storing space which reduces the chances of lower plains getting flooded.
7. Buildings on elevated area:
The buildings in flood prone areas should be constructed on an elevated area and if
necessary on stilts and platform. However, complete flood control in terms of
structural methods of flood protection are neither economically viable nor these are
environment friendly. Therefore, non-structural methods are becoming popular in
mitigating
flood
disaster.
2. Non-structural Measures
Non- structural measures are in the nature of planning and help in “modifying the losses
due to floodsNon-structural measures are particularly applicable to flood-prone areas that
are
not
yet
developed.It
includes:
a) Flood Plain Zoning:
Flood plain zoning, which places restrictions on the use of land on flood plains,
can reduce the cost of flood damage. Local governments may pass laws that
prevent uncontrolled building or development on flood plains to limit flood risks
and to protect nearby property. Landowners in areas that adopt local ordinances or
laws to limit development on flood plains can purchase flood insurance to help
cover the cost of damage from floods.
b) Flood Forecasting and warning:
These are issued for different areas mostly by the Central water
Commission/ Meteorological department and by the State Irrigation/ Flood
Department. However, an effective Warning System is one that can
release warning in advance, i.e. 72hrs, 48hrs and 24hrs. It can change the
existing scenario substantially and render informed decision making in
adopting proper measures towards disaster preparedness, mitigation,
control, planning and management. This kind of advance warning can help
the authorities for better flood preparedness and also effective flood
mitigation. Therefore, initiatives have to be taken to modernize the
operation of Flood Forecasting & Warning by adopting the state of art
technology and integrating it into the forecast and warning dissemination
process.
UNCERTAINTY ANALYSIS:
tradional risk
assessment
proceedure
natural
variability
knowledge
uncertainty
Uncertainty analysis of flood risk management
Uncertainty analysis provides an introduction for flood risk management practitioners, up-to-date
methods for analysis of uncertainty and its use in risk-based decision making. It addresses
decision making for both short-term (real-time forecasting) and long-term (flood risk planning
under change) situations. It aims primarily at technical practitioners involved in flood risk
analysis and flood warning, including hydrologists, engineers, flood modelers, risk analysts and
those involved in the design and operation of flood warning systems. Many experienced
practitioners are now expected to modify their way of working to fit into the new philosophy of
flood risk management. They will also interest and benefit researchers and graduate students
hoping to improve their knowledge of modern uncertainty analysis.
Uncertainty analysis can thereby be applied to performance metrics of direct interest to stakeholders. We
illustrate the framework with an implementation for a hypothetical flood risk management decision. We
discuss possible variants of the framework that could be extended to fields other than flood risk
management.
Objectives of uncertainty analysis for flood risk management in Pakistan
 A generic methodology for flood risk analysis shall be presented, comprising a sequence
of hydrologic, hydraulic and loss modeling. The methodology will analyze flood risks by
investigating possible flood scenarios, their probability of occurrence and their
consequences.
 Uncertainties in the analysis of risks will be integrated by deterministic and stochastic
approaches
 The generic methodology shall be presented and discussed by its application to two cases
studies, where one case study is dedicated to each approach.
Approaches that can be applied in uncertainty analysis for flood risk
management in Pakistan
Approaches for quantifying and processing uncertainties may be summarized as stochastic
concepts, methods employing a set of different assumptions or scenarios and approaches with
interval numbers, for instance fuzzy logic. Stochastic concepts may be solved analytically,
discretely or by Monte Carlo modeling in case of complex systems. Such concepts were
described for instance for the engineering sector or for flood statistics.
There are several approaches that can be applied in uncertainty analysis for flood risk
management in Pakistan:
 the historical developments and emerging trends in flood management;
 the purpose and characteristics of modern flood risk management;
 the goals, objectives and outcomes sought;
 the ongoing challenges in developing and implementing flood risk management in
practice together with some of the common pitfalls and misconception
Sources of uncertainty analysis for flood risk management in Pakistan
 Not all scenarios can be considered, since humankind is not aware of all potential future
Consequences. This applies to natural hazards as well as to health risks. Therefore a part
of the residual risk will remain unknown today.
 Models simplify processes and base on assumptions. Further, the resulting information
refers to a specific spatial and a temporal resolution.

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
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


The selection of appropriate probability distributions and loss functions
Diverging expertise on rare events that have not been observed.
The limited sample size and the sampling period.
Measurement errors of a systematic and a random type. Damage of gauging stations
Temporal changes in the investigated phenomena
Omitted correlation of parameters
Subjective weighting of effects such as integration and trade-offs of social, economic and
environmental aspects within the risk analysis.
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