1. Introduction
Over the last few decades, climate change has increased the frequency and severity of hydro-meteorological disasters in many regions of the world [
1]. Among them, floods are the most recurring and catastrophic hazards, and can cause severe physical, social, and economic damage and loss. The leading measures of flood impact tend to focus on direct damage to physical assets, painting a picture of what is exposed and to what degree. Much less is understood about who is exposed to floods and where, which could increase the likelihood of a natural hazard turning into a social disaster. In this context, it is vital to have a clear understanding of who is vulnerable to flood impacts and where, which can help support the planning and targeting of interventions [
2].
In Pakistan, flood is the most frequent and costly natural disaster, which is likely to increase due to climate change [
3,
4]. While planning is unlikely to fully prevent floods and their consequent impacts, it is possible to quantify flood risk and mitigate these impacts. Flood impacts are not equally distributed among different groups of people, due to their differential exposure and socioeconomic characteristics. Flood exposure is often higher for the socially vulnerable population, due to their poor socio-economic conditions (e.g., financial issues, substandard housing, socially isolated), and thus they are more likely to experience heightened impacts and losses. For example, not everybody residing in flood-prone areas is physically capable of hearing, seeing, and moving, comprehending the danger, and carrying out what they must do to plan for or escape the flood. Consequently, some people have higher exposure and vulnerability to floods, and are less capable of preparing for, dealing with, and recovering from floods [
5,
6,
7,
8,
9]. There is a clear interconnection between exposure to threats and vulnerability: high exposure can increase vulnerability and vice versa. For example, residing in unsafe locations or proximity to hazards can illustrate low socio-economic status (as addressed by the PAR model of vulnerability) [
10].
Social vulnerability is a socially constructed phenomenon attributed to changes in the biophysical and built environment. It depends on the susceptibility or fragilities of society to external threats. Such susceptible conditions are attributed to demographic and socio-economic inequalities among social groups within societies. Social vulnerability analysis has been broadly used as a tool to evaluate the pre-existing conditions or characteristics of individuals or a society that affect their ability to prepare for, respond to, and recover from natural hazards [
11]. It entails identifying the susceptibility or fragilities of the exposed people, understanding where the greatest need may be—before, during, and after a disaster—and is deemed a crucial step towards reducing the consequences of natural hazards [
12]. Similarly, flood exposure maps with spatial variability can help inform community planners to effectively allocate resources and provide emergency management agencies with a better understanding and background before taking action, setting priorities, and developing long-term risk reduction strategies. Social vulnerability can have multiple forms: it can be the state of a system before the event, the likelihood of outcomes in terms of economic losses and lives lost, and it can also be the lack of capacity to face and recover quickly when disaster strikes. The latter deals with ‘resilience’, which refers to the ability of people or a society to respond effectively to hazards; resist, absorb, and minimize the adverse impacts; recover functionality; and adapt in a way that allows for learning and thriving. Information on social vulnerability not only depends on susceptibility to the exposed elements, but also on the resilience to resist or return to an acceptable structural or functional level [
13,
14,
15]. However, in social vulnerability studies, resilience and vulnerability are often separately examined. Less attention has been paid to the varied influence of exposure and resilience components of social vulnerability [
16,
17,
18]. In this study, therefore, we conducted an integrated analysis, combining social vulnerability and geospatial analysis, to evaluate the extent to which a system (a household, in this case) is exposed to floods, and its susceptibility (predisposition of at-risk elements associated with households) in conjunction with its ability (or inability) to cope, recover, or basically adapt.
Different methods to assess or determine hazards and vulnerability to flooding have evolved through ongoing research and practice in recent decades [
12,
19,
20,
21]. Among them, two distinct method types are deterministic modelling and parametric approaches. Deterministic modelling approaches use physically based modelling approaches (e.g., hydraulic modelling, flood inundation modelling, etc.) to estimate flood hazard/probability of particular event. They are coupled with damage assessment models which estimate economic consequence to provide an assessment of flood risk in an area. Parametric approaches, such as the Flood Vulnerability Index (FVI) [
22], aim to use readily available data to build a picture of the vulnerability of an area. This approach has evolved from several concerns, such as the internal characteristics of a system, and global climate change and the political and institutional characteristics of a system. The parametric approach comprises vulnerability assessments in order to minimize the impact of flooding, and also to increase resilience in the affected system [
22]. In recent years, decision-making approaches have also been used in research for flood vulnerability analysis [
23]. Examples of decision-making approaches are the analytical hierarchy process [
24], Delphi [
25], and TOPSIS [
23,
26], among others. However, the major limitation of these methods is determining the interdependency among factors [
27].
Parametric approaches have been widely used by researchers to measure multiple dimensions of vulnerability [
13,
19,
23], For example: the Environmental Vulnerability Index (EVI) [
28]; the Composite Vulnerability Index for Small Island States (CVISIS) [
29]; the Global Risk and Vulnerability Index (GRVI) [
30]; the Climate Vulnerability Index (CVI) [
31]; the Social Vulnerability Index (SoVI) [
11], FVI [
13], etc. Balica et al. [
22] identified that deterministic approaches have considerable limitations over parametric methods (e.g., FVI) in flood vulnerability assessments. Deterministic approaches have a better scientific base, but limited evaluation ability of vulnerability [
22]. FVI gives a wider evaluation, but is less rigorous, and could be used to decide where a deterministic model is necessary. In this study, we conducted an integrated analysis, by combining an index-based system and geospatial analysis to identify areas with high flood exposure, social vulnerability, and their leading drivers. Integrated studies are well suited for analyzing and visualizing spatially varying linkages among physical and social dimensions of vulnerability to hazards. Integrated analysis can perform better in identifying biophysical and socioeconomic inequalities, and in predicting likely impacts and losses [
5,
32]. It can provide a more holistic view of the flooding problem, and can help advance our understanding of vulnerability science [
33,
34].
Numerous sets of social vulnerability indicators for natural hazards exist, such as the Social Vulnerability Index for Disaster Management [
35], Social Determinants of Vulnerability Framework [
36], and Social Vulnerability Index (SoVI) [
11]. Additionally, flood-specific social vulnerability indicator sets include the Cologne flood indicators based on the MOVE (Methods for the Improvement of Vulnerability Assessment in Europe) framework in Germany [
37], the Social Flood Vulnerability Index in England and Wales [
38], and the Urban Municipality Flood Vulnerability Index in Brazil [
39]. However, despite numerous pieces of work on indicators of social vulnerability and resilience, there is no definitive and conclusive set of indicators, or a methodology for developing indicators. Indicators are context-specific, and often vary from one region to another depending on human systems and local environment. Additionally, some statistical methods (such as principal components analysis) used to develop indices and/or indicator sets, which can be influenced by data availability, are challenging for policymakers to understand, and problematic to replicate, as the outputs are only pertinent to the time period and geographical area covered by the analysis. However, summarizing indicators into a single index value can provide simplicity of interpretation.
In Pakistan, researchers have assessed vulnerability in various contexts (i.e., natural hazards and environmental change). However, research on social vulnerability and integrated analysis in the context of flooding hazards is still lacking. Although emergency management agencies are aware of the factors that drive social vulnerability, there is limited information on how socio-economic inequalities and exposure factors play a role in flood disaster impacts, and how their interaction can increase vulnerability. This study attempted to conduct an integrated analysis of flood exposure and social vulnerability in Charsadda District, Khyber Pakhtunkhwa, Pakistan.
Our study has unique academic value in the field of social vulnerability assessment:
- i.
First, we emphasize the importance of integrating the exposure component into social vulnerability assessments. For example, exposure indicators, such as elevation and distance to the river, can be the highest contributing factors linked with high vulnerability. Many previous studies on social vulnerability assessments only use socio-demographic indicators, which may only reflect the susceptibility of local communities [
40,
41,
42,
43];
- ii.
Second, we use the household survey data as input for extracting and calculating indicators for local communities. Most previous index studies mainly use census data for data input, which does not necessarily reflect the ground truth of local communities. Current empirical validation studies have shown that existing census-based social vulnerability and community resilience indicators cannot sufficiently explain the disaster impacts of local communities [
44,
45]. By using household survey data, we can integrate more meaningful exposure, susceptibility, and resilience indicators into social vulnerability assessments;
- iii.
Third, we discover some unique social vulnerability indicators specific for rural communities in the face of flood disasters. For example, rural households with weak economic capacity are more likely to reside nearby flood-prone areas with cheaper land prices, and rural households with larger household sizes are more likely to have a higher proportion of highly susceptible family members such as the elderly, children, and the disabled.
The remainder of this paper is organized as follows:
Section 2 briefly describes the background of the study area.
Section 3 presents the conceptual framework.
Section 4 states the materials and methods.
Section 5 present and evaluates the results of flood exposure and social vulnerability analysis, followed by a discussion in
Section 6. Finally,
Section 7 concludes the obtained findings, contributions, and limitations of this study.
2. Study Area
Pakistan is a highly flood-prone country. The country faces the impacts of frequent and severe seasonal floods, mainly in the monsoon period. The 2010 flood event was considered the century’s worst disaster [
46], causing 1985 fatalities, affecting 515 health facilities, 2.1 million houses, 20.2 million people, and damaging agricultural land of approximately 2.4 million hectares [
47,
48]. Pakistan, being an agricultural country, has a widespread canal and river system which, due to poor management, often results in flooding and causes damages to the people and communities residing in the floodplains and canal/river catchments. Land-use change, socio-economic development, inadequate (poor maintenance) or insufficient drainage systems, and human encroachments over the channels further intensify water runoff, worsening flooding hazards and their impacts on local inhabitants [
49]. According to the National Disaster Management Authority of Pakistan, out of 145 districts in the country (as of the administrative boundaries of 2010), 113 were classified as located in medium to very high flood-risk zones [
50]. Over the last two decades, Khyber Pakhtunkhwa (KP) province has experienced many catastrophic floods [
51]. Most of the districts in KP province are facing frequent and devastating floods, mainly due to the Swat and Kabul Rivers [
52]. The reference map of the study area is shown in
Figure 1.
Charsadda District, which is the focal point of this study, is one of the most severely flood-affected districts in the country, with relatively widespread casualties and losses. The district is located between 71°53′ to 71°28′ east longitudes and 34°03′ to 34°38′ north latitudes. Geographically, the district covers an area of 996 km
2 and is home to several rivers and streams, including the Swat and Kabul Rivers, where flooding is a frequent phenomenon during the monsoon season. There are many reasons behind recurrent flooding in Charsadda District, including climate change, heavy rainfall, and human interventions in flood plain areas. In the flooding events of 2010, it was the Swat and Kabul Rivers that devastated and inundated a large part of the study area. As depicted in
Figure 2, in the 2010 flooding event, the discharge of Swat River reached 8495 cubic meters per second. Heavy rainfall occurred (27–30 July 2010) which exceeded the capacity of the river channels, and they were unable accommodate the discharge water.
Most of the people in the district are engaged in agriculture and horticulture activities for purposes related to their livelihoods. Those practices are generally observed around main rivers, streams, and branches in the basin. Intensive agriculture activities have resulted in massive deposits in the riverbeds, causing rainwater to exceed the rivers’ capacities and overflow to the floodplains. Most of the villages near these rivers have been severely affected by floods, giving us a suitable study area for the conducted assessment. Six union councils (UCs) were selected for the present study based on the assessment reports of the Provincial Disaster Management Authority of Khyber Pakhtunkhwa (PDMA-KP). The total population of Charsadda District is about 1,616,198 (1.6 million), with 36,240 in UC Umar Zai, 15,263 in UC Hisar Yasinzai, 14,426 in UC Turangzai, 11,719 in UC Agra, 9737 in UC Tarnab, and 9681 in UC Daulat Pura [
53], representing the surveyed sites.
6. Discussion
This study’s objective was to quantify flood exposure and social vulnerability of households to floods in Charsadda District, using an indicator-based approach. Developing a conceptual framework (based on the core part of the MOVE framework) for understanding social vulnerability was a crucial step in this study. While conceptual frameworks already existed for understanding biophysical and socio-economic vulnerabilities, resilience, and susceptibility, this is the first time—to our knowledge—that these frameworks have been combined to create a practical framework for social vulnerability analysis. In particular, using the MOVE framework means that the conceptualization of social vulnerability used in this study was robust and consistent with previous research. It gives prominence to all aspects of vulnerability and resilience, regardless of data availability; each dimension is still represented as best as possible with the data available. Furthermore, the framework shows how a lack of resilience is not only an important aspect of social vulnerability, but that other components—such as exposure and susceptibility—also influence social vulnerability.
These indicators provide an important tool for managing disaster risk by providing objective data about social vulnerability in the population to inform disaster risk reduction activities. For the case study of Charsadda, 17 indicators were identified and implemented for the practical investigation of social vulnerability. The findings showed that the southern area, including Agra, Daulat Pura, and Hisar Ysinzai, were the most vulnerable communities. This is mainly because these southern UCs have the highest value of exposure and, specifically, have the highest number of flood locations, lowest elevations, and shortest distances from rivers compared with other UCs. Because of their location in low-elevated areas and nearby the rivers, when precipitation events occur in Charsadda District, these southern UCs are more likely to experience flood disasters and suffer casualties and losses.
Another important reason is that the households with high flood exposure also have weak economic capacity, which can be reflected in the fact that most UCs, especially southern UCs, have low values of resilience for indicators R3 (secondary income sources) and R5 (financial capacity for recovery). This is mainly because people with weak economic capacity are often forced to reside close to rivers in flood hazard zones, where the land is comparatively cheaper, and thus could experience more frequent floods. Coupling with high exposure and low economic capacity, the southern areas in Charsadda District are more likely to have high values of social vulnerability. Our findings are in line with previous studies [
8,
69], which have shown that a household’s location has a positive relationship with vulnerability, and households constructed in proximity to rivers indicate weak socio-economic capacity, and are more likely to be affected by flooding disasters. In order to reduce the social vulnerability of these southern UCs, local governments are suggested to conduct flood risk reduction activities with emphases on reducing flood exposure, for example, by facilitating low-income households’ relocation and enabling them to move their house to higher-elevated areas. For households who are not willing to move, the local government may provide financial assistance to these households enabling them to have a better disaster response capacity and recovery capacity. Similarly, external support is also crucial to the households with high flood exposure and weak economic capacity, especially to strengthen and uplift the economic capacity of the households by the provision of diversified livelihood and employment opportunities, which might reduce the poverty rate and improve the recovery capacity [
70].
Because the UCs in the case study area are rural communities, the relationships between indicators are different from previous studies for urban communities. This is reflected in our indicators of susceptibility. For example, Kuhlicke, et al. [
63] four case studies across Europe found that larger households generally have more manpower and thus are anticipated to reduce susceptibility through education and financial assistance. However, our findings show that larger households are often highly susceptible groups because most family members are elderly and children. During disaster events, populations with disabilities, children, and the elderly are considered the most vulnerable groups, as they need special care which limits their ability during emergencies to move to safer locations [
71,
72,
73,
74]. Additionally, larger households experience more health problems and financial burdens after flooding events [
75]. In addition, our findings also showed that a high percentage of household heads were either illiterate or had a low level of education. Illiteracy affects the population’s ability to seek flood risk awareness, understand precautionary measures, and adopt preventive and mitigative measures, which eventually makes them more susceptible to the impacts of flooding hazards [
8,
11,
64,
76]. Based on these findings, it is suggested that local governments give more attention to large households’ capacity for flood disaster preparedness, response, and recovery in rural communities.
Our study has unique academic value in the field of social vulnerability assessments. First, we emphasize the importance of integrating the exposure component into social vulnerability assessments. Our analysis results also showed that exposure indicators such as elevation and distance to the river can be the greatest contributing factors linked with high vulnerability. Even for a UC with a moderate value of susceptibility and a high value of resilience (i.e., Daulat Pura), its final score of social vulnerability can be very high—Daulat Pura ranked in second place among six UCs. The survey data also showed that the households living in the UCs with a high value of exposure experienced the highest number of casualties and losses during flooding disasters. Many previous studies on social vulnerability assessments only use socio-demographic indicators, which may only reflect the susceptibility of local communities [
40,
41,
42,
43]. Second, we used household survey data as input for extracting and calculating indicators for local communities. Most previous index studies have mainly used census data for data input, which does not necessarily reflect the ground truth of local communities. Current empirical validation studies have shown that existing census-based social vulnerability and community resilience indicators cannot sufficiently explain the disaster impacts of local communities [
44,
45]. By using the household survey data, we can integrate more meaningful exposure, susceptibility, and resilience indicators into social vulnerability assessments. Third, we discovered some unique social vulnerability indicators specifically for rural communities facing flooding disasters. For example, rural households with weak economic capacity are more likely to reside nearby flood-prone areas with cheaper land prices, and rural households with larger household sizes are more likely to have a higher proportion of highly susceptible family members, such as the elderly, children, and the disabled.
Despite these contributions, this research has some limitations. For example, all the respondents interviewed were men because, according to local norms and strong cultural values, women are inhibited from coming forward. Secondly, this research was carried out in six UCs only, and our household survey data were from a limited number of households in each UC (around 30–40). Although we conducted the stratified sampling to ensure a certain level of precision and confidence, it is unavoidable that the responses from the sampled households cannot reflect the whole population of our case study area. Future studies are encouraged to conduct random sampling techniques (e.g., telephone interviews via a random digital dialing method) to collect household information on social vulnerability factors and disaster risk reduction. Third, for flood exposure analysis, we used limited indicators such as elevation, flooded/inundated area, closeness to the river, and past flood experience. Future studies need to focus on a more in-depth analysis, considering a wide range of physical (e.g., hydraulic modelling, flood damage/inundation modelling, etc.), social and environmental components, in order to design policies and implement them.
This research has paved the way for various future projects, including determining whether these indicators and framework can be applied to other hazards. The framework was designed to be useful for both natural disasters and climate change, and it aligns with existing collections of vulnerability measures reported worldwide. The core elements of susceptibility, resilience, and exposure, which are likely to be applicable to a number of hazards, have been incorporated into a broad notion of vulnerability to natural hazards. Susceptible groups, such as children, the elderly, and those with disabilities (mental and/or physical), would be more vulnerable to the harmful consequences of any catastrophe. Additionally, regardless of the natural hazard, people who are exposed and lack resilience, whether due to a lack of financial capacity, housing, social integration, risk awareness, and preparedness, are expected to be more vulnerable. In this context, the indicators and framework could be applicable to other potential threats such as earthquakes and tsunamis, heatwaves, wildfires, and other severe weather events. More analysis could be undertaken to examine social vulnerability indicators and frameworks objectively, and see how this framework is relevant to other hazards.
The framework and indicators might also be helpful in the event of a health crisis, such as the COVID-19 pandemic. COVID-19′s possible impacts, in the context of Pakistan, include sickness and death, stress and anxiety, lockdowns, border closures, financial challenges, loss of employment, possibly limited access to medicinal and educational facilities, psychological impacts, and household crowdedness. In an influenza pandemic, the factors that influence high-risk populations are close to those that influence floods, such as poverty, overcrowded and substandard housing, children, refugees, the elderly, and those with special healthcare needs or disabilities and compromised immune systems [
77]. Furthermore, in countries hit hard by the COVID-19 pandemic, the elderly aged 60 plus tended to be at a greater risk of severe sickness and/or death if COVID-19 was contracted. The resemblance of vulnerability indicators to floods and the influenza pandemic means that social vulnerability indicators may be examined for COVID-19 in Pakistan, with further indicators to be studied, such as the elderly aged 60 plus and individuals in jobs more likely to suffer financially as a result of society’s approach to handling the pandemic. More research should be completed to see if these indicators are useful in the health sector.
More studies should be undertaken to see how well this framework and accompanying indicators work with longer-term climate-related events, such as rising sea levels and drought. Some changes to the framework and further indicators, such as those related to the long-term adaptive capacity of the population to climate change, may be needed. Future vulnerability, such as exposure to predicted future hazardous areas (considering the effects of climate change), demographic patterns of population, and vulnerability trends, may all be addressed. Future drivers of vulnerability, such as the inability to obtain protection in disaster areas in the future, may also be considered.
7. Conclusions and Recommendations
Floods are the most damaging catastrophic phenomena worldwide. Therefore, understanding flood vulnerability is necessary for effective risk management and sustainable development. However, there is a lack of an accurate and reliable approach for identifying rural communities’ social vulnerability to flood hazards. In this study, a Social Vulnerability Index was specifically developed for flood-prone rural communities. An indicator-based approach was used to identify social vulnerability and its key components using the example of flooding in Charsadda District. Compared with earlier collections of social vulnerability indicators, we designed a conceptual framework, integrating the exposure component with social vulnerability to make it more empirically valid in the context of rural areas in Pakistan. A set of theoretically sound indicators relating to flood exposure and social vulnerability were identified, and then the most empirically sound ones were shortlisted in the context of Pakistan, based on local experts’ opinions.
For flood exposure analysis, we adopted geospatial methods such as elevation, flooded locations, distance from the river, and flood-inundated area, followed by validation assessments through field surveys. At the first step, flood inundation and locations maps were prepared using LANDSAT ETM 7 and band 5 images, documentary sources of PDMA-KP, and field surveys. Then, two data layers (distance from rivers and elevation) were derived from the spatial database, maps were produced using the FR method, and the results were plotted in ArcGIS. Finally, the flood exposure data were combined with the flood outcome and socio-economic indicator data, collected from a well-sampled household survey, to produce social vulnerability maps. The most significant indicators linked with high vulnerability were exposure-related indicators. For example, the findings showed that the southern area, including Agra, Daulat Pura, and Hisar Ysinzai were the most vulnerable communities. This is mainly because these southern UCs have the highest number of flood locations, lowest elevations, shortest distances from rivers, larger household sizes including the elderly, children, and women, illiteracy, and weak financial capacity. Our study confirms that vulnerability does not exclusively rely on susceptibility, but instead on multiple components of exposure, resilience, and adaptive capacities that act together and influence the vulnerability of individuals or a society. Based on the overall assessments, the proposed approach in this study was concluded as objective and applicable.
Understanding dominant indicators and areas where high social vulnerability and high exposure converge can inform the authorities, governments, and community planners to perform proper actions in order to prevent and mitigate both social and physical flood vulnerabilities in the future. To strengthen local planning for emergencies, inform response efforts during a disaster, and improve peoples’ resilience, interventions must be applied to the areas and indicators identified, and have a significant influence on household exposure, susceptibility, and resilience levels in the study area. For example, in the study area, most of the houses were located in low-elevated areas and in close proximity to rivers; therefore, effective land-use policies should be formulated and implemented to strictly prohibit new constructions in floodplains and facilitate low-income households’ relocation, enabling them to move to higher-elevated areas. For households who are not willing to move, the local government may provide financial assistance to these households, enabling them to have a better disaster response capacity and recovery capacity. Similarly, guided head spurs and marginal embankments can be constructed along rivers to minimize flood impacts in the future. Furthermore, to increase flood risk awareness, proper training sessions must be conducted with the at-risk communities to improve their flood risk awareness and capacity to understand early warnings and measures to be taken to mitigate, prepare, respond to, and recover from flooding disasters. Most households with high flood exposure areas were also found to have weak economic capacity; therefore, external support is also crucial, especially to strengthen and uplift the economic capacity of households by the provision of diversified livelihood and employment opportunities, which might reduce poverty rates and improve recovery capacity. The proposed measures will effectively reduce household flood exposure and vulnerability, and increase their resilience towards flooding or other hazards in the future.