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:

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 MonitoringIn 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 MitigationIt 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

accumualte water in near by areas

Pathwaywater entered in the city, homes and building

Receptor

damage of lives and wealth

Consequence

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:

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:

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. Hydrological2. 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 re-occurrence 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:

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:

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:

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

Year

Value of Property Damaged (Rs in Million)

Unadjusted

Value of Property Damaged (Rs in Million)

Adjusted

Lives Lost Villages Affected

1950 199.80 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

2005 Not Reported 59 1,931

Asset value

at purchase price

Gross concept (Constant value)

Net concept (depreciation considered)

at actual price

Gross concept

Net concept

2006 Not Reported 541 2,477

2007 Not Reported 586 6498

2008 Not Reported 157 800

2009 Not Reported 99 89

2010 819,381.00 819,381.00 1961 14,316

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:

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:

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:

inundation areas with water depth land use distribution specific asset values damage functions

damage within each grid cell can be calculated as:

DLnij = CLn

ij * 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 as-set/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.

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.Structural2. 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:

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

tradional risk assessment proceedure

natural variability

knowledge uncertainty

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.

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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