Coastal Erosion Risk Assessment Research Articles

Using geospatial business intelligence paradigm to design a multidimensional conceptual model for efficient coastal erosion risk assessment

One of the main challenges in Coastal Erosion Risk Assessment (CERA) is integrating and analysis of conflicting data in various time periods and spatial scales through dissimilar environmental, social, and economic criteria. Currently, Geographical Information Systems (GIS) are widely used in risk assessment despite their drawbacks and limitations as transactional systems for multi-scales, multi-epochs, and multi-themes analysis. Hence, an analytical conceptual framework is proposed in this paper based on geospatial business intelligence paradigm to develop a Spatial Multidimensional Conceptual Model (SMCM) to assess coastal erosion risk. The model is designed based on Spatial On-Line Analytical Processing (SOLAP) platform, on the top of both analytical and transactional paradigms, to allow fast synthesis of cross-tabulated data and easy comparisons over space, scales, epochs, and themes. This objective is achieved through a comprehensive integration of multiple environmental, social, and economic criteria as well as their interactions at various scales. It also takes into account multiple elements at risk such as people, infrastructure, and built environment as different dimensions of analysis. Using this solution allows decision makers to benefit from on-demand, interactive, and comprehensive information in a way that is not possible using GIS alone. The developed model can easily be adapted for any other coastal region through the proposed framework to perform risk assessment. The advantages and drawbacks of the proposed framework are also discussed and new research perspectives are presented.

On the coastal erosion risk assessment indexes

China is one of the most severely affected countries by coastal erosion. About 70% of the sandy beaches and most of muddy tidal flat in open water regions are erode. Coastal erosion results in the width of beach being narrowed, bathing beach destruction, coast-protection facilities and roads collapse, and wetland deterioration. These destructions bring many losses to the local people. However, previous coastal erosion studies focused on the hazard of erosion and paid less attention to the risk of erosion. Therefore, it’s necessary to study the mechanism of coastal erosion and build the coastal erosion risk assessment system for the effective coastal management. On the basis of the existed researches, this paper builds the coastal erosion risk assessment index system which contains hazard index system and vulnerability index system. The index system is expected to provide a practical theoretical basis for coastal erosion risk assessment.

Multivariate return periods of sea storms for coastal erosion risk assessment

Abstract. The erosion of a beach depends on various storm characteristics. Ideally, the risk associated with a storm would be described by a single multivariate return period that is also representative of the erosion risk, i.e. a 100 yr multivariate storm return period would cause a 100 yr erosion return period. Unfortunately, a specific probability level may be associated with numerous combinations of storm characteristics. These combinations, despite having the same multivariate probability, may cause very different erosion outcomes. This paper explores this ambiguity problem in the context of copula based multivariate return periods and using a case study at Durban on the east coast of South Africa. Simulations were used to correlate multivariate return periods of historical events to return periods of estimated storm induced erosion volumes. In addition, the relationship of the most-likely design event (Salvadori et al., 2011) to coastal erosion was investigated. It was found that the multivariate return periods for wave height and duration had the highest correlation to erosion return periods. The most-likely design event was found to be an inadequate design method in its current form. We explore the inclusion of conditions based on the physical realizability of wave events and the use of multivariate linear regression to relate storm parameters to erosion computed from a process based model. Establishing a link between storm statistics and erosion consequences can resolve the ambiguity between multivariate storm return periods and associated erosion return periods.

GEOGRAFIA URBANA QUE FAZEMOS

This paper presents an overview about the state-of-art of studies on oceanic sandy beaches from the State of São Paulo, within the Coastal Geomorphology point of view. These studies embrace a sort of thematic issues, in special: beach profile monitoring, textural (grain size) parameters, heavy minerals assemblage and related indices, beach sedimentary dynamics, beach sedimentary budget, sediment transport patterns (morpho-textural and wave modeling methods), long term shoreline changes (remote sensing analyses), morphodynamic classification, coastal erosion and associated risk, and environmental sensitivity for oil spill. Some results related to morphodynamic classification, grain size parameters behavior, longshore drift patterns, and coastal erosion (indicators, causes and risk assessment) are showed for the seven morphodynamic sectors that this coast is comprised.

PRAIAS ARENOSAS OCEÂNICAS DO ESTADO DE SÃO PAULO (BRASIL): SÍNTESE DOS CONHECIMENTOS SOBRE MORFODINÂMICA, SEDIMENTOLOGIA, TRANSPORTE COSTEIRO E EROSÃO COSTEIRA

This paper presents an overview about the state-of-art of studies on oceanic sandy beaches from the State of São Paulo, within the Coastal Geomorphology point of view. These studies embrace a sort of thematic issues, in special: beach profile monitoring, textural (grain size) parameters, heavy minerals assemblage and related indices, beach sedimentary dynamics, beach sedimentary budget, sediment transport patterns (morpho-textural and wave modeling methods), long term shoreline changes (remote sensing analyses), morphodynamic classification, coastal erosion and associated risk, and environmental sensitivity for oil spill. Some results related to morphodynamic classification, grain size parameters behavior, longshore drift patterns, and coastal erosion (indicators, causes and risk assessment) are showed for the seven morphodynamic sectors that this coast is comprised.

Risk Assessment of Coastal Erosion for Suitable Rural Planning

ベトナム北部紅河デルタは、人口が集中し、土地利用の高度化が顕著である。この地域では集約農業が行われているが、洪水や高潮災害などの水関連災害に脆弱である。特に南部デルタ沿岸域では近年、海岸侵食による被害が大きくなっており農地被害のみならず、沿岸部の地域社会に軋轢と組織変化をもたらしている。それにもかかわらず、海岸線変化とそれによって引き起こされる被害の予測に関する議論はほとんどなされていないばかりか、地域防災計画も皆無に等しい。本研究では、土地利用計画が未策定である紅河デルタを実例として、JERS-1合成開口レーダ (SAR) による1994年から1998年までの衛星画像8枚を重ね合わせ、海岸線を得ることにより海岸線動態値 (CDI) を求め、対象地域の侵食、堆積特性を明らかにした。さらに、海岸線動態値および海抜と堤防データを利用してリスクマップを作成し、海岸侵食の観点から現状の土地利用の脆弱性評価を試みた。

Coastal Erosion Risk Assessment, Shoreline Retreat Rates and Causes of Coastal Erosion Along the State of São Paulo Coast, Brazil

Monitoring on coastal erosion problems along the São Paulo shoreline have been carrying out by the author since mid the 80’s, including almost 87% of the whole 430 km length of sandy beaches. Eleven types of indicators of coastal erosional processes have been recognized, which have been attributed to seventeen causes, among them ten correspond to natural mechanisms and seven are due to anthropogenic interference. In this paper is presented rates of shoreline retreat based on the Bruun Rule application for six of the most threatened beaches, for a period as long as 56 years. Risk assessment is also estimated for these six beaches based on two criteria: (i) the total number (sum) of types of coastal erosion indicators found along the shoreline (frequency among the 11 types) and (ii) general spatial distribution (percentage of surface area) of coastal erosion indicators along the shoreline. Causes and effects of the coastal erosional processes are discussed for these six beaches. Results reveal high rates of shoreline retreat, even in non-urbanized areas, as well demonstrate that the six beaches are at very-high risk. Moreover, they indicate that natural mechanisms are very important as cause of coastal erosional processes in São Paulo, sometimes most them the human-induced causes. These studies have widely been supporting the State Plan for Coastal Zone Management, in order to create special rules for occupation and some activities along the shoreline, including engineering works, building and sand beach exploration. Besides, results are being recorded in a geoenvironmental information system for the Coastal Zone of the State of São Paulo (Project SIIGAL), which is in phases of implantation.