ABSTRACT The effectiveness of disaster risk management and financing mechanisms depends on the ac... more ABSTRACT The effectiveness of disaster risk management and financing mechanisms depends on the accurate assessment of current and future hazard exposure. The increasing availability of detailed data offers policy makers and the insurance sector new opportunities to understand trends in risk, and to make informed decisions on the ways to deal with these trends. In this paper we show how comprehensive property level information can be used for the assessment of exposure to flooding on a national scale, and how this information can contribute to discussions on possible risk financing practices. The case-study used is the Netherlands, which is one of the countries most exposed to flooding globally, and which is currently undergoing a debate on strategies for the compensation of potential losses. Our results show that flood exposure has increased rapidly between 1960 and 2012, and that the growth of the building stock and its economic value in flood prone areas has been higher than in not flood prone areas. We also find that property values in flood prone areas are lower than those in not flood prone areas. We argue that the increase in the share of economic value located in potential flood prone areas can have a negative effect on the feasibility of private insurance schemes in the Netherlands. The methodologies and results presented in this study are relevant for many regions around the world where the effects of rising flood exposure create a challenge for risk financing.
The effectiveness of disaster risk management and financing mechanisms depends on an accurate ass... more The effectiveness of disaster risk management and financing mechanisms depends on an accurate assessment of current and future hazard exposure. The increasing availability of detailed data offers policy makers and the insurance sector new opportunities to understand trends in risk, and to make informed decisions on ways to deal with these trends. In this paper we show how comprehensive property level information can be used for the assessment of exposure to flooding on a national scale, and how this information provides valuable input to discussions on possible risk financing practices. The case study used is the Netherlands, which is one of the countries most exposed to flooding globally, and which is currently undergoing a debate on strategies for the compensation of potential losses. Our results show that flood exposure has increased rapidly between 1960 and 2012, and that the growth of the building stock and its economic value in flood-prone areas has been higher than in non-flood-prone areas. We also find that property values in flood-prone areas are lower than those in non-flood-prone areas. We argue that the increase in the share of economic value located in potential flood-prone areas can have a negative effect on the feasibility of private insurance schemes in the Netherlands. The methodologies and results presented in this study are relevant for many regions around the world where the effects of rising flood exposure create a challenge for risk financing.
In this article, we propose an integrated direct and indirect flood risk model for small- and lar... more In this article, we propose an integrated direct and indirect flood risk model for small- and large-scale flood events, allowing for dynamic modeling of total economic losses from a flood event to a full economic recovery. A novel approach is taken that translates direct losses of both capital and labor into production losses using the Cobb-Douglas production function, aiming at improved consistency in loss accounting. The recovery of the economy is modeled using a hybrid input-output model and applied to the port region of Rotterdam, using six different flood events (1/10 up to 1/10,000). This procedure allows gaining a better insight regarding the consequences of both high- and low-probability floods. The results show that in terms of expected annual damage, direct losses remain more substantial relative to the indirect losses (approximately 50% larger), but for low-probability events the indirect losses outweigh the direct losses. Furthermore, we explored parameter uncertainty using a global sensitivity analysis, and varied critical assumptions in the modeling framework related to, among others, flood duration and labor recovery, using a scenario approach. Our findings have two important implications for disaster modelers and practitioners. First, high-probability events are qualitatively different from low-probability events in terms of the scale of damages and full recovery period. Second, there are substantial differences in parameter influence between high-probability and low-probability flood modeling. These findings suggest that a detailed approach is required when assessing the flood risk for a specific region.
Flood risk in coastal zones is projected to increase due to climate change and socioeconomic chan... more Flood risk in coastal zones is projected to increase due to climate change and socioeconomic changes. Over the last decades, population growth, increases in wealth, and urban expansion have been found to be the main causes for increasing losses in coastal areas. These changes may, however, be offset by appropriate management measures. The main goal of this study is to assess future changes in flood risk and the effectiveness of flood risk adaptation measures for the coastal zone in Flanders, Belgium. In order to achieve this, we set up a modeling framework to assess the future flood risk of the Belgian coast including climatic and socioeconomic projections, and used this model to assess the effectiveness of two spatial adaptation measures: compartmentalization and land-use zoning. In this modeling framework, a land-use model, an inundation model, and a damage model were combined to calculate expected annual damage. Results show that without adaptation measures, future flood risk would increase substantially. Compartmentalization would result in an average flood risk reduction of approximately 50 % for both the baseline situation and future scenarios. Land-use zoning would result in smaller flood risk reductions, averaging between 6 and 10 %. Except for the most extreme climate change scenario, compartmentalization would successfully offset the combined adverse effects of socioeconomic growth and climate change on flood risk for this case study. For both compartmentalization and zoning, large differences have been found in their effectiveness at the local level, implying that the choice of adaptation measures should be tailored to local characteristics.
Flood damage assessments are often based on stage-damage curve (SDC) models that estimate economi... more Flood damage assessments are often based on stage-damage curve (SDC) models that estimate economic damage as a function of flood characteristics (typically flood depths) and land use. SDCs are developed through a site-specific analysis, but are rarely adjusted to economic circumstances in areas to which they are applied. In Italy, assessments confide in SDC models developed elsewhere, even if empirical damage reports are collected after every major flood event. In this paper, we have tested, adapted and extended an up-to-date SDC model using flood records from Northern Italy. The model calibration is underpinned by empirical data from compensation records. Our analysis takes into account both damage to physical assets and losses due to foregone production, the latter being measured amidst the spatially distributed gross added value.
ABSTRACT The effectiveness of disaster risk management and financing mechanisms depends on the ac... more ABSTRACT The effectiveness of disaster risk management and financing mechanisms depends on the accurate assessment of current and future hazard exposure. The increasing availability of detailed data offers policy makers and the insurance sector new opportunities to understand trends in risk, and to make informed decisions on the ways to deal with these trends. In this paper we show how comprehensive property level information can be used for the assessment of exposure to flooding on a national scale, and how this information can contribute to discussions on possible risk financing practices. The case-study used is the Netherlands, which is one of the countries most exposed to flooding globally, and which is currently undergoing a debate on strategies for the compensation of potential losses. Our results show that flood exposure has increased rapidly between 1960 and 2012, and that the growth of the building stock and its economic value in flood prone areas has been higher than in not flood prone areas. We also find that property values in flood prone areas are lower than those in not flood prone areas. We argue that the increase in the share of economic value located in potential flood prone areas can have a negative effect on the feasibility of private insurance schemes in the Netherlands. The methodologies and results presented in this study are relevant for many regions around the world where the effects of rising flood exposure create a challenge for risk financing.
The effectiveness of disaster risk management and financing mechanisms depends on an accurate ass... more The effectiveness of disaster risk management and financing mechanisms depends on an accurate assessment of current and future hazard exposure. The increasing availability of detailed data offers policy makers and the insurance sector new opportunities to understand trends in risk, and to make informed decisions on ways to deal with these trends. In this paper we show how comprehensive property level information can be used for the assessment of exposure to flooding on a national scale, and how this information provides valuable input to discussions on possible risk financing practices. The case study used is the Netherlands, which is one of the countries most exposed to flooding globally, and which is currently undergoing a debate on strategies for the compensation of potential losses. Our results show that flood exposure has increased rapidly between 1960 and 2012, and that the growth of the building stock and its economic value in flood-prone areas has been higher than in non-flood-prone areas. We also find that property values in flood-prone areas are lower than those in non-flood-prone areas. We argue that the increase in the share of economic value located in potential flood-prone areas can have a negative effect on the feasibility of private insurance schemes in the Netherlands. The methodologies and results presented in this study are relevant for many regions around the world where the effects of rising flood exposure create a challenge for risk financing.
In this article, we propose an integrated direct and indirect flood risk model for small- and lar... more In this article, we propose an integrated direct and indirect flood risk model for small- and large-scale flood events, allowing for dynamic modeling of total economic losses from a flood event to a full economic recovery. A novel approach is taken that translates direct losses of both capital and labor into production losses using the Cobb-Douglas production function, aiming at improved consistency in loss accounting. The recovery of the economy is modeled using a hybrid input-output model and applied to the port region of Rotterdam, using six different flood events (1/10 up to 1/10,000). This procedure allows gaining a better insight regarding the consequences of both high- and low-probability floods. The results show that in terms of expected annual damage, direct losses remain more substantial relative to the indirect losses (approximately 50% larger), but for low-probability events the indirect losses outweigh the direct losses. Furthermore, we explored parameter uncertainty using a global sensitivity analysis, and varied critical assumptions in the modeling framework related to, among others, flood duration and labor recovery, using a scenario approach. Our findings have two important implications for disaster modelers and practitioners. First, high-probability events are qualitatively different from low-probability events in terms of the scale of damages and full recovery period. Second, there are substantial differences in parameter influence between high-probability and low-probability flood modeling. These findings suggest that a detailed approach is required when assessing the flood risk for a specific region.
Flood risk in coastal zones is projected to increase due to climate change and socioeconomic chan... more Flood risk in coastal zones is projected to increase due to climate change and socioeconomic changes. Over the last decades, population growth, increases in wealth, and urban expansion have been found to be the main causes for increasing losses in coastal areas. These changes may, however, be offset by appropriate management measures. The main goal of this study is to assess future changes in flood risk and the effectiveness of flood risk adaptation measures for the coastal zone in Flanders, Belgium. In order to achieve this, we set up a modeling framework to assess the future flood risk of the Belgian coast including climatic and socioeconomic projections, and used this model to assess the effectiveness of two spatial adaptation measures: compartmentalization and land-use zoning. In this modeling framework, a land-use model, an inundation model, and a damage model were combined to calculate expected annual damage. Results show that without adaptation measures, future flood risk would increase substantially. Compartmentalization would result in an average flood risk reduction of approximately 50 % for both the baseline situation and future scenarios. Land-use zoning would result in smaller flood risk reductions, averaging between 6 and 10 %. Except for the most extreme climate change scenario, compartmentalization would successfully offset the combined adverse effects of socioeconomic growth and climate change on flood risk for this case study. For both compartmentalization and zoning, large differences have been found in their effectiveness at the local level, implying that the choice of adaptation measures should be tailored to local characteristics.
Flood damage assessments are often based on stage-damage curve (SDC) models that estimate economi... more Flood damage assessments are often based on stage-damage curve (SDC) models that estimate economic damage as a function of flood characteristics (typically flood depths) and land use. SDCs are developed through a site-specific analysis, but are rarely adjusted to economic circumstances in areas to which they are applied. In Italy, assessments confide in SDC models developed elsewhere, even if empirical damage reports are collected after every major flood event. In this paper, we have tested, adapted and extended an up-to-date SDC model using flood records from Northern Italy. The model calibration is underpinned by empirical data from compensation records. Our analysis takes into account both damage to physical assets and losses due to foregone production, the latter being measured amidst the spatially distributed gross added value.
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Papers by Elco Koks