Managing flood loss
Thursday, 11 October 2007
Dr K. M. Nabiul Islam in the first part of a four-part article
FLOODS are important sources of disaster in Bangladesh. A total of 28 major river floods occurred in the past five decades. Flat topography, heavy rainfalls, geographical location, trans-boundary flows and the act of the global warming including socio-economic and flood conditions add complications to Bangladesh's flood problem.
Bangladesh is once again passing through a crisis, caused by the 2007 flood in just three years after the 2004 event. Alarmingly still, the flood has hit the country for the second time in the middle of last month.
Flood impacts and related issues: An account of damages to the economy caused by floods shows that there has been a marked rising trend of economic losses. While many factors are responsible, a fundamental cause which provokes disaster proneness is human encroachment into hazard-prone areas, worsened by increasing risks created by rapid urbanisation, flawed development strategies (e.g., unplanned urbanisation, deforestation) and climate change. It is encouraging, however, to note that the number of reported killed due to river floods in Bangladesh has a clear decreasing trend.
Flood loss to agricultural sector: An analysis of damage to wet season's rice crops shows that historically Bangladesh is damage- prone by 3.7 per cent of production annually (averaged over 37 years). Of this, Aus is subject to annual damage by 4.4 per cent and Aman by 3.4 per cent.
As argued in various studies, some floods can often be adjusted in agriculture (e.g. through changes in cropping patterns), and are seldom harmful. Flooding often increases the productivity of agricultural land through increase in soil fertility. The agricultural shortfalls in the years/seasons of floods are to some extent compensated by above normal production in the years/seasons in the aftermath.
In the disastrous flood of 1998, for example, Aman production fell short by nearly 21 per cent below the normal trend production. The shortfall in wet season rice crops together (Aus+Aman) was 20 per cent below the trend production. By contrast, the production of the dry season rice crop (Boro), however, was 10 per cent above the normal trend in the same year. Similar are the findings for the flood of 2004 when the shortfall in wet season rice crops together (Aus + Aman) was 6.0 per cent below the trend production. The production of the dry season rice crop (Boro), however, was 2.0 per cent above the normal trend. Similarly, in all the years of flood and years in the aftermath, the Boro productions were above the normal trend.
Linking damage to rice production with corresponding flood-affected areas, evidently, both for Aman individually and wet season (Aus + Aman) rice crops together, the correlations are found to be negative, as expected, and also statistically significant. For the dry season crop (i.e. Boro), however, the correlation is found to be positive and highly significant.
This suggests that the farmers put additional efforts into the production of the dry season crop (Boro), in recovering losses of the wet season crops. Replanting of the Aman crop after the flood damage is also frequently helpful in compensating the seasonal losses. The recovery process is also often facilitated by increased provision of irrigation and modern inputs and other extension services.
Flood loss to non-agricultural sectors: The Asian Development Bank (ADB) sponsored appraisal of flood losses to the whole economy caused by the 1998 flood shows that the non-agricultural sectors together (e.g., infrastructure and commercial sectors), including the non-crop sector suffered enormous losses, constituting 51 per cent of the total loss with the agriculture sector (crop plus non-crop) suffering 49 per cent of the total loss. The picture with the 2004 flood is yet more significant when the non-agricultural sectors suffered loss accounting for as high as 74 per cent of the total loss, with the remaining 26 per cent suffered to the agriculture (crop plus non-crop) sector.
The growths in population and urbanisation are gradually outstripping the carrying capacity of local ecosystems. With vast populations and properties, Dhaka city, for example, is expanding down into the low lying areas on periphery in most unplanned ways, which has posed enormous environmental threats. Urban flooding has recently emerged as alarming, which is created by drastic reduction of low-lying areas and thereby destruction of natural drainage system resulting from rapid urbanization and infrastructure development. Drainage congestion continued in the DND area for more than a month, even with a short duration flood such as the 2007 event. This is a burning example of water logging due to drainage congestion which occurred as a result of not adequately considering the natural inflow and outflow of water during the planning and implementation stage. Poor operations and maintenances of the structure also have contributed to the disaster.
Urban flood losses are thus becoming more and more important in Bangladesh. Controlled flooding is obviously not an appropriate strategy in urban areas, as often as the case in agriculture. Protection of urban and commercial centres thus demands a high priority
Linkage effects of flooding: The impacts of floods on society and economies are complex. Especially in an urban economy, innumerable inter-dependencies exist among the sectors and the sub-sectors, which eventually give rise to external economies, making the measure of linkage effects (or multiplier effects) even complex.
Unlike in the developed economies, in Bangladesh, following that there are limited scope for 'transferability' and '?redundancies' within the economy the linkage effects or multiplier effects of flooding are likely to be considerable. An analysis shows that in the industry sector, as a whole, linkage effects of flooding in Bangladesh estimate as high as 158 per cent of primary indirect impact (i.e., production loss). This is a type of flood impacts which is seldom recognized in the total flood loss assessment, even in developed countries.
Flood impacts on prices: In addition to abrupt fall in employment and purchasing power in the aftermath of floods, price hikes hit the poor in the worst way. An analysis of trends in rice prices illustrates that maximum deviations (above normal trend) occur in the aftermath of severe floods as a short-run effect. One can, however, notice that in the 1998 flood adverse price effects were not evident implying that the flood was managed successfully, at least in terms of price hikes.
Interface of flooding with poverty: In Bangladesh, as research experience demonstrates, the poor and relatively the smaller enterprises are more vulnerable to flood hazard. They are also worse off in linkage terms. Flood losses have cumulative effects on the most vulnerable; some are even subsequently uprooted. Empirical evidence in this context shows that the low-income occupants (thus also low-cost houses) are relatively more vulnerable to floods. The lower the level of house categories (and income classes) the higher the percentage of damages to their total asset values.
On an average, the poorest-type house suffers (in terms of losses proportional to values) four, five and three times as much, compared to that suffered by the richest-type house, in a river, flash and tidal flood respectively.
Intuitively, floods not only deepen poverty levels but also may help widen the income gap between the rich and the poor. Another analysis shows that lower land-ownership people (also lower income-categories) suffer higher inundation levels and are hence indeed more exposed to flood risks. From an analysis on World Food Programme (WFP) data for 92 Upazilas one can find a close positive relationship between percentage of flooded areas and percentage of ultra people.
Price hikes compounded by a fall in real wages cause malnutrition and the existing poor health of the poor further deteriorates, with the likelihood of many becoming crippled in the long run. On the other hand, 'Poverty is one of the main reasons why many people persist on hazardous floodplains', and they have 'little locational choice'. As the poor are not equipped to cope with floods, they become poorer because of their poverty, suggesting that disasters and poverty operate in a vicious cycle.
Loss of property due to flood immensely contributes to rural-urban migration scenario, subsequently causing social and environmental degradation in urban areas. Many vulnerable households are often compelled to take loans at high interest rate to recover flood damages without any repayments, eventually losing their belongings, which led them to migrate in the urban areas to search for a new livelihood.
Health effects of flooding: Floods bring about immense health impacts. The long-run effects of flooding on morbidity and subsequent decline in productivity forms one of the major indirect impacts. During wide-spread and catastrophic floods in Bangladesh, poor victims are confronted with the shortage of food and employment.
Shortage of food becomes particularly distressing in respect of children and women population. With the acute shortage of edible food and pure water, the victims are immediately confronted with the outbreak of water-borne diseases. An empirical evidence shows that floodings clearly have a positive influence on the incidence of diarrhoeal diseases.
Flood loss assessment methods: Finally, and, perhaps, more importantly in Bangladesh, especially in non-agricultural sectors, hitherto there exists little basic research on flood losses and their assessments methods. Flood research has almost been limited to only appraisals or evaluation studies in the form of reports which again focus largely on agricultural losses. There is no systematic attempt of flood loss data collection, especially for non-agricultural sectors.
Following the lack of damage data and methodology, the loss assessment from the 2004 flood carried out by various agencies and the government, for example, appears to have been based on arbitrary methods, the loss estimates thus made ranging from Taka 100 billion (10,000 crore) to Taka 420 billion (42,000 crore).
It is thus important to improve the knowledge of how natural hazards magnified by urbanisation can cause havoc to lives and property. It is important to understand the benefits and limitations of all flood mitigation choices. In order to 'deal with' a natural hazard such as flood, it is imperative to generate a flood loss database so that a consistent, well-informed decision making is possible.
The author is a Senior Research Fellow, Bangladesh Institute of Development Studies.
To be continued
FLOODS are important sources of disaster in Bangladesh. A total of 28 major river floods occurred in the past five decades. Flat topography, heavy rainfalls, geographical location, trans-boundary flows and the act of the global warming including socio-economic and flood conditions add complications to Bangladesh's flood problem.
Bangladesh is once again passing through a crisis, caused by the 2007 flood in just three years after the 2004 event. Alarmingly still, the flood has hit the country for the second time in the middle of last month.
Flood impacts and related issues: An account of damages to the economy caused by floods shows that there has been a marked rising trend of economic losses. While many factors are responsible, a fundamental cause which provokes disaster proneness is human encroachment into hazard-prone areas, worsened by increasing risks created by rapid urbanisation, flawed development strategies (e.g., unplanned urbanisation, deforestation) and climate change. It is encouraging, however, to note that the number of reported killed due to river floods in Bangladesh has a clear decreasing trend.
Flood loss to agricultural sector: An analysis of damage to wet season's rice crops shows that historically Bangladesh is damage- prone by 3.7 per cent of production annually (averaged over 37 years). Of this, Aus is subject to annual damage by 4.4 per cent and Aman by 3.4 per cent.
As argued in various studies, some floods can often be adjusted in agriculture (e.g. through changes in cropping patterns), and are seldom harmful. Flooding often increases the productivity of agricultural land through increase in soil fertility. The agricultural shortfalls in the years/seasons of floods are to some extent compensated by above normal production in the years/seasons in the aftermath.
In the disastrous flood of 1998, for example, Aman production fell short by nearly 21 per cent below the normal trend production. The shortfall in wet season rice crops together (Aus+Aman) was 20 per cent below the trend production. By contrast, the production of the dry season rice crop (Boro), however, was 10 per cent above the normal trend in the same year. Similar are the findings for the flood of 2004 when the shortfall in wet season rice crops together (Aus + Aman) was 6.0 per cent below the trend production. The production of the dry season rice crop (Boro), however, was 2.0 per cent above the normal trend. Similarly, in all the years of flood and years in the aftermath, the Boro productions were above the normal trend.
Linking damage to rice production with corresponding flood-affected areas, evidently, both for Aman individually and wet season (Aus + Aman) rice crops together, the correlations are found to be negative, as expected, and also statistically significant. For the dry season crop (i.e. Boro), however, the correlation is found to be positive and highly significant.
This suggests that the farmers put additional efforts into the production of the dry season crop (Boro), in recovering losses of the wet season crops. Replanting of the Aman crop after the flood damage is also frequently helpful in compensating the seasonal losses. The recovery process is also often facilitated by increased provision of irrigation and modern inputs and other extension services.
Flood loss to non-agricultural sectors: The Asian Development Bank (ADB) sponsored appraisal of flood losses to the whole economy caused by the 1998 flood shows that the non-agricultural sectors together (e.g., infrastructure and commercial sectors), including the non-crop sector suffered enormous losses, constituting 51 per cent of the total loss with the agriculture sector (crop plus non-crop) suffering 49 per cent of the total loss. The picture with the 2004 flood is yet more significant when the non-agricultural sectors suffered loss accounting for as high as 74 per cent of the total loss, with the remaining 26 per cent suffered to the agriculture (crop plus non-crop) sector.
The growths in population and urbanisation are gradually outstripping the carrying capacity of local ecosystems. With vast populations and properties, Dhaka city, for example, is expanding down into the low lying areas on periphery in most unplanned ways, which has posed enormous environmental threats. Urban flooding has recently emerged as alarming, which is created by drastic reduction of low-lying areas and thereby destruction of natural drainage system resulting from rapid urbanization and infrastructure development. Drainage congestion continued in the DND area for more than a month, even with a short duration flood such as the 2007 event. This is a burning example of water logging due to drainage congestion which occurred as a result of not adequately considering the natural inflow and outflow of water during the planning and implementation stage. Poor operations and maintenances of the structure also have contributed to the disaster.
Urban flood losses are thus becoming more and more important in Bangladesh. Controlled flooding is obviously not an appropriate strategy in urban areas, as often as the case in agriculture. Protection of urban and commercial centres thus demands a high priority
Linkage effects of flooding: The impacts of floods on society and economies are complex. Especially in an urban economy, innumerable inter-dependencies exist among the sectors and the sub-sectors, which eventually give rise to external economies, making the measure of linkage effects (or multiplier effects) even complex.
Unlike in the developed economies, in Bangladesh, following that there are limited scope for 'transferability' and '?redundancies' within the economy the linkage effects or multiplier effects of flooding are likely to be considerable. An analysis shows that in the industry sector, as a whole, linkage effects of flooding in Bangladesh estimate as high as 158 per cent of primary indirect impact (i.e., production loss). This is a type of flood impacts which is seldom recognized in the total flood loss assessment, even in developed countries.
Flood impacts on prices: In addition to abrupt fall in employment and purchasing power in the aftermath of floods, price hikes hit the poor in the worst way. An analysis of trends in rice prices illustrates that maximum deviations (above normal trend) occur in the aftermath of severe floods as a short-run effect. One can, however, notice that in the 1998 flood adverse price effects were not evident implying that the flood was managed successfully, at least in terms of price hikes.
Interface of flooding with poverty: In Bangladesh, as research experience demonstrates, the poor and relatively the smaller enterprises are more vulnerable to flood hazard. They are also worse off in linkage terms. Flood losses have cumulative effects on the most vulnerable; some are even subsequently uprooted. Empirical evidence in this context shows that the low-income occupants (thus also low-cost houses) are relatively more vulnerable to floods. The lower the level of house categories (and income classes) the higher the percentage of damages to their total asset values.
On an average, the poorest-type house suffers (in terms of losses proportional to values) four, five and three times as much, compared to that suffered by the richest-type house, in a river, flash and tidal flood respectively.
Intuitively, floods not only deepen poverty levels but also may help widen the income gap between the rich and the poor. Another analysis shows that lower land-ownership people (also lower income-categories) suffer higher inundation levels and are hence indeed more exposed to flood risks. From an analysis on World Food Programme (WFP) data for 92 Upazilas one can find a close positive relationship between percentage of flooded areas and percentage of ultra people.
Price hikes compounded by a fall in real wages cause malnutrition and the existing poor health of the poor further deteriorates, with the likelihood of many becoming crippled in the long run. On the other hand, 'Poverty is one of the main reasons why many people persist on hazardous floodplains', and they have 'little locational choice'. As the poor are not equipped to cope with floods, they become poorer because of their poverty, suggesting that disasters and poverty operate in a vicious cycle.
Loss of property due to flood immensely contributes to rural-urban migration scenario, subsequently causing social and environmental degradation in urban areas. Many vulnerable households are often compelled to take loans at high interest rate to recover flood damages without any repayments, eventually losing their belongings, which led them to migrate in the urban areas to search for a new livelihood.
Health effects of flooding: Floods bring about immense health impacts. The long-run effects of flooding on morbidity and subsequent decline in productivity forms one of the major indirect impacts. During wide-spread and catastrophic floods in Bangladesh, poor victims are confronted with the shortage of food and employment.
Shortage of food becomes particularly distressing in respect of children and women population. With the acute shortage of edible food and pure water, the victims are immediately confronted with the outbreak of water-borne diseases. An empirical evidence shows that floodings clearly have a positive influence on the incidence of diarrhoeal diseases.
Flood loss assessment methods: Finally, and, perhaps, more importantly in Bangladesh, especially in non-agricultural sectors, hitherto there exists little basic research on flood losses and their assessments methods. Flood research has almost been limited to only appraisals or evaluation studies in the form of reports which again focus largely on agricultural losses. There is no systematic attempt of flood loss data collection, especially for non-agricultural sectors.
Following the lack of damage data and methodology, the loss assessment from the 2004 flood carried out by various agencies and the government, for example, appears to have been based on arbitrary methods, the loss estimates thus made ranging from Taka 100 billion (10,000 crore) to Taka 420 billion (42,000 crore).
It is thus important to improve the knowledge of how natural hazards magnified by urbanisation can cause havoc to lives and property. It is important to understand the benefits and limitations of all flood mitigation choices. In order to 'deal with' a natural hazard such as flood, it is imperative to generate a flood loss database so that a consistent, well-informed decision making is possible.
The author is a Senior Research Fellow, Bangladesh Institute of Development Studies.
To be continued