The impact of uncertain precipitation data on insurance loss estimates using a flood catastrophe model

Catastrophe risk models used by the insurance industry are likely subject to significant uncertainty, but due to their proprietary nature and strict licensing conditions they are not available for experimentation. In addition, even if such experiments were conducted, these would not be repeatable by other researchers because commercial confidentiality issues prevent the details of proprietary catastrophe model structures from being described in public domain documents. However, such experimentation is urgently required to improve decision making in both insurance and reinsurance markets. In this paper we therefore construct our own catastrophe risk model for flooding in Dublin, Ireland, in order to assess the impact of typical precipitation data uncertainty on loss predictions. As we consider only a city region rather than a whole territory and have access to detailed data and computing resources typically unavailable to industry modellers, our model is significantly more detailed than most commercial products. The model consists of four components, a stochastic rainfall module, a hydrological and hydraulic flood hazard module, a vulnerability module, and a financial loss module. Using these we undertake a series of simulations to test the impact of driving the stochastic event generator with four different rainfall data sets: ground gauge data, gauge-corrected rainfall radar, meteorological reanalysis data (European Centre for Medium-Range Weather Forecasts Reanalysis-Interim; ERA-Interim) and a satellite rainfall product (The Climate Prediction Center morphing method; CMORPH). Catastrophe models are unusual because they use the upper three components of the modelling chain to generate a large synthetic database of unobserved and severe loss-driving events for which estimated losses are calculated. We find the loss estimates to be more sensitive to uncertainties propagated from the driving precipitation data sets than to other uncertainties in the hazard and vulnerability modules, suggesting that the range of uncertainty within catastrophe model structures may be greater than commonly believed.

Flood forecasting in large rivers with data-driven models

Results from the application of adaptive neuro-fuzzy inference system (ANFIS) to forecast water levels at 3 stations along the mainstream of the Lower Mekong River are reported in this paper. The study investigated the effects of including water levels from upstream stations and tributaries, and rainfall as inputs to ANFIS models developed for the 3 stations. When upstream water levels in the mainstream were used as input, improvements to forecasts were realized only when the water levels from 1 or at most 2 upstream stations were included. This is because when there are significant contributions of flow from the tributaries, the correlation between the water levels in the upstream stations and stations of interest decreases, limiting the effectiveness of including water levels from upstream stations as inputs. In addition, only improvements at short lead times were achieved. Including the water level from the tributaries did not significantly improve forecast results. This is attributed mainly to the fact that the flow contributions represented by the tributaries may not be significant enough, given that there could be large volume of flow discharging directly from the catchments which are ungauged, into the mainstream. The largest improvement for 1-day forecasts was obtained for Kratie station where lateral flow contribution was 17 %, the highest for the 3 stations considered. The inclusion of rainfall as input resulted in significant improvements to long-term forecasts. For Thakhek, where rainfall is most significant, the persistence index and coefficient of efficiency for 5-lead-day forecasts improved from 0.17 to 0.44 and 0.89 to 0.93, respectively, whereas the root mean square error decreased from 0.83 to 0.69 m.

Assessment of the damage caused by flood rains and landslides in association with hurricane Michelle, october 2001: implications for economic, social and environmental development

Preface This study was prepared for the Government of Jamaica following the significant physical damage and economic losses that the country sustained as a result of flood rains associated with the development of Hurricane Michelle. The Planning Institute of Jamaica (PIOJ) submitted a request for assistance in undertaking a social, environmental and economic impact assessment to the Economic Commission for Latin America and the Caribbean (ECLAC) on 14 November 2001. ECLAC responded with haste and modified its work plan to accommodate the request. A request for training in the use of the ECLAC Methodology to be delivered to personnel in Jamaica was deferred until the first quarter of 2002, as it was impossible to mount such an initiative at such short notice. This appraisal considers the consequences of the three instances of heavy rainfall that brought on the severe flooding and loss of property and livelihoods. The study was prepared by three members of the ECLAC Natural Disaster Damage Assessment Team over a period of one week in order to comply with the request that it be presented to the Prime Minister on 3 December 2001. The team has endeavoured to complete a workload that would take two weeks with a team of 15 members working assiduously with data already prepared in preliminary form by the national emergency stakeholders. There is need for training in disaster assessment as evidenced by the data collected by the Jamaican officials engaged in the exercise. Their efforts in the future will be more focused and productive after they have received training in the use of the ECLAC Methodology. This study undertakes a sectoral analysis leading to an overall assessment of the damage. It appraises the macroeconomic and social effects and proposes some guidelines for action including mitigating actions subsequent to the devastation caused by the weather system. The team is grateful for the efforts of the Office of Disaster Preparedness and Emergency Management (ODPEM), the associated government ministries and agencies, the Statistical Institute of Jamaica (STATIN), the Planning Institute of Jamaica and the Inter American Development Bank (IDB) for assistance rendered to the team. Indeed, it is the recommendation of the team that STATIN is poised to play a pivotal role in any disaster damage assessment and should be taken on board in that regard. The direct and indirect damages have been assessed in accordance with the methodology developed by ECLAC (1). The results presented are based on the mission's estimates. The study incorporates the information made available to the team and evidence collected in interviews and visits to affected locations. It is estimated that the magnitude of the losses exceeds the country's capacity to address reparations and mitigation without serious dislocation of its development trajectory. The government may wish to approach the international community for assistance in this regard. This appraisal is therefore designed to provide the government and the international community with guidelines for setting national and regional priorities in rehabilitation and reconstruction or resettlement programmes. A purely economic conception of the problem would be limited. A more integrated approach would have a human face and consider the alleviation of human suffering in the affected areas while attending to the economic and fiscal fallout of the disaster. Questions of improved physical planning, watershed management, early warning, emergency response and structural preparedness for evacuation and sheltering the vulnerable population are seen as important considerations for the post disaster phase. Special attention and priority should be placed on including sustainability and increased governance criteria in making social and productive investments, and on allocating resources to the reinforcing and retrofitting of vulnerable infrastructure, basic lifelines and services as part of the reconstruction and rehabilitation strategy. The Jamaican society and government face the opportunity of undertaking action with the benefit of revised paradigms, embarking on institutional, legal and structural reforms to reduce economic, social and environmental vulnerability. The history of flood devastation in the very areas of Portland and St. Mary shows a recurrence of flooding. Accounts of flooding from the earliest recorded accounts pertaining to 1837 are available. Recurrences in 1937, 1940, 1943 and 2001 indicate an ever-present probability of recurrence of similar events. The Government may wish to consider the probable consequences of a part of its population living in flood plains and address its position vis-à­¶is land use and the probability of yet another recurrence of flood rains. (1) ECLAC/IDNDR, Manual for estimating the Socio-Economic Effects of Natural Disasters, May,1999.

Análise de risco a inundação na cidade de Alenquer - Estado do Pará

A cidade de Alenquer, localizada na região do Baixo Amazonas do Estado do Pará, sofre historicamente com a ameaça de inundação. Todos os anos, na época da enchente, o furo Surubiú aumenta seu nível, inundando as partes mais baixas da cidade. A presente dissertação analisa o risco a inundação existente na cidade de Alenquer proporcionando instrumentos para a gestão e melhorias das ações do poder público. A análise de ameaça se baseou em uma metodologia que agrega dados históricos, hidrológicos, mapa de construção participativo e trabalho de campo com GPS, identificado três áreas distintas na cidade: (i) área de alta suscetibilidade, anualmente afetada pelas inundações, abrange 8,4% da área da cidade (ii) área de moderada suscetibilidade, apenas atingida quando observado os maiores índices fluviométricos e (iii) área que mesmo na maiores enchentes não é atingida. O cálculo da vulnerabilidade ocorreu a partir da construção de um índice que inclui dados do censo de demográfico, trabalho de campo para a identificação dos elementos essenciais e unidades de respostas. Após a aplicação do índice verificou-se que dos 17 setores da cidade, cinco apresentam alta vulnerabilidade, e os demais moderada vulnerabilidade. Na análise de risco os dados de vulnerabilidade e ameaças foram integrados e novamente três zonas na cidade foram identificadas (i) a zona de alto risco corresponde a 9,45 % da cidade, onde há grande concentração de elementos essenciais e algumas unidades de respostas, o que provoca danos sociais e econômicos quando da ocorrência de inundação (ii) zona de moderado risco, 30% da cidade e (iii) zona de baixo risco que corresponde a 60,55% da cidade. O Plano Diretor do município foi analisado com alguns questionamentos para verificar a inclusão da temática de ameaça, vulnerabilidade e risco nesse documento, após a análise pode se concluir a falta de abordagem dessa temática no plano diretor. Os resultados obtidos com a pesquisa são importantes para subsidiar políticas publicas e os documentos exigidos pela Defesa Civil quando da ocorrência de desastres.

Vulnerabilidade ambiental ao óleo em ambiente fluvial: estudo de caso rio Tietê/Reservatório de Barra Bonita

Pós-graduação em Geociências e Meio Ambiente - IGCE

Evaluation of the vulnerability of families assisted in Primary Care in Brazil

Objective: to characterize the profiles of families in the area covered by a Primary Health Center and to identify those in a vulnerable situation. Method: this is an epidemiological, observational, cross-sectional and quantitative study. 320 home visits were made, defined by a random sample of the areas covered by the Urban Center 1 in the city of Sao Sebastiao, in Brazil's Federal District. A structured questionnaire was used for data collection, elaborated based on the Family Development Index (FDI). Results: there was a predominance of young families, women, and low levels of schooling. The FDI permitted the identification of families in situations of "high" and "very high" vulnerability. The most critical dimensions were: "access to knowledge" and "access to work". Conclusion: the study indicated the importance of greater investments in the areas of education, work and income, and highlighted the need for the use of a wider concept of vulnerability by the health services.

Vulnerability and robustness indices against blackouts in power grids

In this dissertation some novel indices for vulnerability and robustness assessment of power grids are presented. Such indices are mainly defined from the structure of transmission power grids, and with the aim of Blackout (BO) prevention and mitigation. Numerical experiments showing how they could be used alone or in coordination with pre-existing ones to reduce the effects of BOs are discussed. These indices are introduced inside 3 different sujects: The first subject is for taking a look into economical aspects of grids’ operation and their effects in BO propagation. Basically, simulations support that: the determination to operate the grid in the most profitable way could produce an increase in the size or frequency of BOs. Conversely, some uneconomical ways of supplying energy are shown to be less affected by BO phenomena. In the second subject new topological indices are devised to address the question of "which are the best buses to place distributed generation?". The combined use of two indices, is shown as a promising alternative for extracting grid’s significant features regarding robustness against BOs and distributed generation. For this purpose, a new index based on outage shift factors is used along with a previously defined electric centrality index. The third subject is on Static Robustness Analysis of electric networks, from a purely structural point of view. A pair of existing topological indices, (namely degree index and clustering coefficient), are combined to show how degradation of the network structure can be accelerated. Blackout simulations were carried out using the DC Power Flow Method and models of transmission networks from the USA and Europe.

Index-Oriented Methodologies for Landslide Consequence Analysis: An Application to a Mountain Community in the French Alps

Consequence analysis is a key aspect of anchoring assessment of landslide impacts to present and long-term development planning. Although several approaches have been developed over the last decade, some of them are difficult to apply in practice, mainly because of the lack of valuable data on historical damages or on damage functions. In this paper, two possible consequence indicators based on a combination of descriptors of the exposure of the elements at risk are proposed in order to map the potential impacts of landslides and highlight the most vulnerable areas. The first index maps the physical vulnerability due to landslide; the second index maps both direct damage (physical, structural, functional) and indirect damage (socio-economic impacts) of landslide hazards. The indexes have been computed for the 200 km2 area of the Barcelonnette Basin (South French Alps), and their potential applications are discussed.

Organic geochemistry of water and bottom sediments during a seasonal flood in 2006 in the North Dvina River estuary

Heavy contaminant load released into the Northern Dvina River during flooding increased the concentrations of aliphatic (AHC) and polcyclic aromatic (PAH) hydrocarbons in water and bottom sediments. The composition of hydrocarbons was different from that of the summer low flow season. The concentrations of dissolved and particulate AHC ranged from 12 to 106 and from 192 to 599 µg/l, respectively, and bottom sediments contained from 26.2 to 329 µg/g AHC and 4 to 1785 ng/g PAH. As the transformation of AHC occurred at low spring temperatures, the alkane composition was shown to be dominated by terrigenous compounds, whereas more stable PAH showed elevated contents of petrogenic and pyrogenic compounds. It was also shown that the Northern Dvina-Dvina Bay geochemical barrier prevents contaminant input into the White Sea, i.e., acts as a marginal filter.

Hydrocarbons in bottom sediments during a seasonal flood 2005 in the Dvina River estuary

The results of studying hydrocarbons during the flood in May 2005 are discussed. The concentration of aliphatic and polycyclic aromatic hydrocarbons are shown to match their concentrations in water areas with steady input of pollutants. Weathered oil and pyrogenic compounds dominated in their composition. The geochemical barrier the Northern Dvina River-Dvina Gulf is shown to become a filter during floods and prevents pollutants from penetrating into the White Sea.

Risk-based methodology for parameter calibration of a reservoir flood control model

Flash floods are of major relevance in natural disaster management in the Mediterranean region. In many cases, the damaging effects of flash floods can be mitigated by adequate management of flood control reservoirs. This requires the development of suitable models for optimal operation of reservoirs. A probabilistic methodology for calibrating the parameters of a reservoir flood control model (RFCM) that takes into account the stochastic variability of flood events is presented. This study addresses the crucial problem of operating reservoirs during flood events, considering downstream river damages and dam failure risk as conflicting operation criteria. These two criteria are aggregated into a single objective of total expected damages from both the maximum released flows and stored volumes (overall risk index). For each selected parameter set the RFCM is run under a wide range of hydrologic loads (determined through Monte Carlo simulation). The optimal parameter set is obtained through the overall risk index (balanced solution) and then compared with other solutions of the Pareto front. The proposed methodology is implemented at three different reservoirs in the southeast of Spain. The results obtained show that the balanced solution offers a good compromise between the two main objectives of reservoir flood control management

Flood Control Work in Red River, Atchafalaya, and Bayou Boeuf Levee District : hearings before the United States Senate Committee on Commerce, seventy-third Congress, second session. February 5, 1934.

Considers (73) S. 2067.