Climate Change Adaptation Case Study: Benefit-Cost Analysis of Coastal Flooding Hazard Mitigation

The damage Hurricane Sandy caused had far-reaching repercussions up and down the East Coast of the United States. Vast coastal flooding accompanied the storm, inundating homes, businesses, and utility and emergency facilities. Since the storm, projects to mitigate similar future floods have been scrutinized. Such projects not only need to keep out floodwaters but also be designed to withstand the effect that climate change might have on rising sea levels and increased flood risk. In this study, we develop an economic model to assess the costs and benefits of a berm (sea wall) to mitigate the effects of flooding from a large storm. We account for the lifecycle costs of the project, which include those for the upfront construction of the berm, ongoing maintenance, land acquisition, and wetland and recreation zone construction. Benefits of the project include avoided fatalities, avoided residential and commercial damages, avoided utility and municipal damages, recreational and health benefits, avoided debris removal expenses, and avoided loss of function of key transportation and commercial infrastructure located in the area. Our estimate of the beneficial effects of the berm includes ecosystem services from wetlands and health benefits to the surrounding community from a park and nature system constructed along the berm. To account for the effects of climate change and verify that the project will maintain its effectiveness over the long term, we allow the risk of flooding to increase over time. Over our 50-year time horizon, we double the risk of 100- and 500-year flood events to account for the effects of sea level rise on coastal flooding. Based on the economic analysis, the project is highly cost beneficial over its 50-year timeframe. This analysis demonstrates that climate change adaptation investments can be cost beneficial even though they mitigate the impacts of low-probability, high-consequence events.

El agua como factor reordenador del territorio en el caso de las inundaciones de la Universidad de la Sabana en 2011

El objetivo de este estudio de caso es analizar el agua como factor reordenador del territorio, en el caso específico de las inundaciones sucedidas en el 2011 en el territorio de la Universidad de la Sabana. Durante la ola invernal del 2011 todo el país sufrió las consecuencias de los errores en la planeación de los asentamientos humanos. La no inclusión de la gestión del riesgo dentro del Ordenamiento Territorial, sumado la falta de comprensión de las dinámicas del territorio y del rol del agua como factor ordenador del territorio, causaron inundaciones y desastres naturales que afectaron la vida de miles de ciudadanos, entre eso los estudiantes, profesores y demás afectados por las inundaciones de la Universidad de la Sabana.

Regras de operação do reservatório de Magos para controlo de cheias

Face à Directiva 2007/60/CE relativa à avaliação e gestão do risco de inundações, ao Decreto-Lei nº 344/2007 que aprova o Regulamento de Segurança de Barragens, ao aumento de áreas urbanizadas e às projecções dos modelos de clima para o fim do século, que apontam para o aumento da frequência e da intensidade da ocorrência de inundações causadas por eventos de precipitação intensa de curta duração, é crucial a definição de regras de operação nos reservatórios com controlo de cheias. O Reservatório de Magos pertence à bacia hidrográfica do rio Tejo, está situado no Concelho de Salvaterra de Magos e tem como usos principais a rega e o controlo de cheias. Este trabalho tem como objecto de estudo a definição das regras de operação (restrição no caudal descarregado) do Reservatório de Magos para controlo de cheias no troço a jusante. São aplicados o modelo hidrológico HEC-HMS 3.1.0, o modelo hidráulico HEC-RAS 3.1.3 e o modelo de simulação de reservatórios HEC-ResSim 3.O para o cálculo do hidrograma de cheia, da zona inundável e para simulação do balanço de água no reservatório, respectivamente. Como resultado são apresentadas as regras de operação (caudal máximo e mínimo a descarregar) do Reservatório de Magos para controlo da zona inundável a jusante, no caso de um evento de cheia. /ABSTRACT: Based on the Directive 2007/60/CE related to the Assessment and Management of Flood Risks, on the Decree-Law n. o 344/2007 which approves the Regulation for Dam Safety, the increased urban areas and to the projections of climate models by the end of the century which is pointing to an increased frequency and intensity of occurrence of floods caused by intense rainfall events of short duration, establishing rules of operation for flood control in reservoirs becomes crucial. The Magos Reservoir belongs to the river Tagus basin, located in the county of Salvaterra de Magos and has as its main uses the irrigation and flood control. This study aims to establish the rules of operation (flow discharged restriction) of the Reservoir of Magos for flood control in the downstream reach. The methodology used in the present work includes the application of the Hydrological model HEC-HMS 3.1.0, the Hydraulic model HEC-RAS 3.1.3 and a reservoir simulation model HEC-ResSim 3.0 to calculate the hydrograph of peak discharge, floodplain zone and simulate reservoir operations, respectively. As a result, the rules of operation (maximum flow and minimum discharge) of Magos Reservoir for flood control in a downstream reach in case of flood event are presented.

VULNERABILIDAD ECONÓMICA EN ÁREAS DE RIESGO POR AMENAZAS NATURALES: UNA APROXIMACIÓN METODOLÓGICA PARA SU ESTIMACIÓN. EL CASO DE CIUDAD CORTÉS, COSTA RICA

Ciudad Cortés, en un pequeño pueblo localizado al sur del país, que ha sido afectado desde hace varios años por las inundaciones de los ríos Térraba y Balsar, se han estimado los costos de la infraestructura dañada en áreas de alto riesgo. De acuerdo con esta información, se han seleccionado ejemplos de construcciones, realizando cálculos económicos y relacionados con un mapa diseñado con curvas isográficas por cada metro. El mapa final muestra las áreas de riesgo y algunas estrategias para reducir las pérdidas de vidas y propiedades.Abstract:In a small town located in the southern part of the country, that is affected since many years by the floods Térraba and Balsar rivers, we try to estimate the costofthc infrastructure which isbuild in the areas of high risk. According with this information, we seLcct a sample of buildings, made a calculation of its econornic value and related them with a map designed with hipsographic contours each one-meter. We obtain at the end a map that shows risks areas and sorne strategies for reducing ¡oss of lives and properties.