Comprehensive Assessment of Flood Hazard, Vulnerability, and Flood Risk at the Household Level in a Municipality Area: A Case Study of Nan Province, Thailand

Estimating flood hazard, vulnerability, and flood risk at the household level in the past did not fully consider all relevant parameters. The main objective of this study is to improve this drawback by developing a new comprehensive and systematic methodology considering all relevant parameters and their weighting factors. This new methodology is applied to a case study of flood inundation in a municipal area of Nan City in the Upper Nan River Basin in Thailand. Field and questionnaire surveys were carried out to collect pertinent data for input into the new methodology for estimating flood hazard, vulnerability, and risk. Designed floods for various return periods were predicted using flood simulation models for assessing flood risk. The flood risk maps constructed for the return periods of 10–500 years show a substantial increase in flood risk with the return periods. The results are consistent with past flood damages, which were significant near and along the riverbanks where ground elevation is low, population density is high, and the number of household properties are high. In conclusion, this new comprehensive methodology yielded realistic results and can be used further to assess the effectiveness of various proposed flood mitigation measures.

PENERAPAN TEKNIK MODERASI TERHADAP IMPLEMENTASI MODEL PEMBELAJARAN MITIGASI BENCANA DI SEKOLAH DASAR

ABSTRAKPenelitian ini bertujuan untuk mengungkapkan tanggapan dan pendapat guru tentang pelaksanaan model pembelajaran mitigasi bencana dan upaya meningkatkannya di sekolah dasar. Penelitian dilaksanakan terhadap 12 guru SD negeri 1 Sembalun Lombok Timur, NTB. Penelitian deskriptif ini dimulai dengan menampilkan sebuah model pembelajaran mitigasi bencana tanah longsor oleh tim peneliti yang dilanjutkan dengan diskusi struktur pembelajaran mitigasi bencana yang diaplikasikan dari modeling sebelumnya. Hasil penelitian mendapatkan 5 pokok pikiran tentang pelaksanaan model pembelajaran mitigasi bencana tanah longsor, yaitu 1) mengkondisikan peserta didik menghadapi bencana alam dalam proses pembelajaran, 2) guru harus memiliki langkah yang tepat dalam memberikan pemahaman tentang bencana alam dan melakukan demontrasi langsung sehingga peserta didik memahami dengan seksama, 3) guru harus memiliki pengetahuan kebencanaan gempabumi, tsunami, tanah longsor, banjir, angin topan dan gunungapi, 4) guru memberikan contoh pembelajaran mitigasi bencana kepada peserta didik menggunakan alat bantu seperti video, alat mitigasi bencana dan lainnya, 5) pemahaman resiko/bahaya, kerentanan (kelemahan), ancaman dan kemampuan/kekuatan bencana tanah longsor. Kata kunci: teknik moderasi; implementasi model pembelajaran mitigasi bencana; sekolah dasar. ABSTRACTThis study aims to reveal the responses and opinions of teachers about the implementation of the disaster mitigation learning model and efforts to improve it in primary schools. The study was conducted on 12 teachers of SD Negeri 1 Sembalun, East Lombok, NTB. This descriptive study begins by presenting a learning model for landslide disaster mitigation by the research team, followed by a discussion of the disaster mitigation learning structure applied from the previous modeling. The results of the study obtained 5 main ideas about the implementation of the landslide disaster mitigation learning model, namely 1) conditioning students to face natural disasters in the learning process, 2) teachers must have the right steps in providing an understanding of natural disasters and conducting direct demonstrations so that students understand carefully, 3) teachers must have knowledge of earthquakes, tsunamis, landslides, floods, hurricanes and volcanoes, 4) teachers provide examples of disaster mitigation learning to students using tools such as videos, disaster mitigation tools and others, 5) understanding risk/hazard, vulnerability (weakness), threat and capability/strength of landslide disaster. Keywords: moderation techniques; implementation of disaster mitigation learning model; primary school.

Understanding the NEEDS for ACTING: An integrated framework for applying nature-based solutions in Brazil

Nature-Based Solutions (NBS) support the provision of multiple benefits for the environment and society. First idealised in 2008, NBS are recommended by worldwide reports and guidelines as strategies to protect, sustainably manage and restore ecosystems. However, their operationalisation is still in the early stages, especially in developing countries, and only a few studies consider their full potential. This article contributes to this context by developing an integrated framework, with spatial and participatory tools, for analysing flood risk mitigation in Brazil. The approach enables a deep understanding of the societal challenges and vulnerabilities of the area (i.e., NEEDS) for subsequently planning the appropriate NBS (i.e., ACTIONS), with the participation of 255 stakeholders of Campina Grande municipality. Results show mappings of flood-prone areas, in which approximately 52% of the flooded areas will have an increase in the future. Hotspots (i.e., hazard, vulnerability, and exposure) are shown and discussed with four application cases. Finally, multiple benefits of seven NBS alternatives are analysed in 53 scenarios of application, in which the higher rates of reductions are found to combined alternatives. The discussion emphasizes the importance of spatially assessing the ‘needs’ and ‘multiple benefits’ of NBS, including reducing vulnerabilities and increment of resilience.

Application of the Coastal Hazard Wheel for Coastal Multi-Hazard Assessment and Management in the Guang-Dong-Hongkong-Macao Greater Bay Area

The coasts of Guangdong-Hong Kong-Macao Greater Bay Area (GBA) are facing threats and challenges from rising sea levels, frequent extreme events and human intervention. In this study, the Coastal Hazard Wheel (CHW) was used to classify the coasts of GBA, assess its hazard change from 2010 to 2020, identify hazards hotspots and explore available coastal management options. The results show that the coastal types of GBA in 2010 and 2020 are consistent, with delta/low estuary island and hard rock slope as the main types. GBA is vulnerable to ecosystem disruption, saltwater intrusion, gradual inundation and flooding hazards. Compared with 2010, the high risk proportion of each hazard in 2020 decreased significantly, but the high risk of flooding increased slightly. All kinds of hazards are interdependent and influenced by each other. The Pearl River Estuary, the east bank of Yamen Waterway, the west bank of Huangmao Sea and Dapeng Bay show very high hazard vulnerability, and the flooding risk is the highest. Soft measures such as coastal zoning, tsunami warning systems, wetland restoration and hazard simulation are most widely used in coastal management. CHW is applicable to GBA’s coastal hazard vulnerability assessment, which provides a case study for coastal risk assessment of GBA and has certain reference significance for hazard management and sustainable development for the Bay Area.

Numerical Assessment of Coastal Multi-hazard Vulnerability in Tokyo Bay

Many bays in the world are threatened by coastal hazards such as storm surge, river flood and tsunami. Since most of the existing studies have been focused on one or two of them, in this study, the assessment of coastal vulnerability caused by the three hazards was the research target. Inundation simulation is a widely used and straightforward way in coastal vulnerability assessments; however, it is computationally expensive, and considering an increase in the number of cases in multi-hazard analysis, an efficient method was proposed using an estimated overflow volume without computing inundation, which was validated by comparing with inundation simulation. It shows that when free overflow is dominant, this method is consistent with inundation simulation approach. Using Tokyo Bay as a study area, the efficient method was then applied to multi-hazard vulnerability assessment. By comparing the overflow volume maps and maximum anomaly distribution along the coasts for four types of hazards (worst storm surge; worst concurrent storm surge and river flood; worst concurrent storm surge, river flood and Tokai-Tonankai earthquake tsunami; worst concurrent storm surge, river flood and Tokyo inland earthquake tsunami), we investigated the characteristics of different types of hazards and identified the difference between single hazard and multi-hazards. The characteristic of overflow volume along the coasts is similar to that of maximum anomaly distribution, especially for only storm surge case, the multi-hazard case combining storm surge and river flood, and the multi-hazard case combining storm surge, Tokyo inland earthquake tsunami and river flood. However, for multi-hazard case combining storm surge, Tokai-Tonankai earthquake tsunami and river flood, only by the maximum anomaly distribution, it cannot reflect the real overflow volume condition. For only storm surge case and multi-hazard case combining storm surge and river flood, the head of the bay suffers the highest vulnerability while for multi-hazard cases combining storms surge, tsunami and river flood, the difference of vulnerability in the north and south of the bay is not significant. The difference of superposing method and concurrent method for computing multi-hazards was also compared. It was found that the linear superposing method tends to overestimate the total water elevation in coastal region; however, in the coasts where superposing method underestimates the multi-hazard anomalies, upgrading dikes needs to be considered by policymakers.

Mapping Risk to Land Subsidence: Developing a Two-Level Modeling Strategy by Combining Multi-Criteria Decision-Making and Artificial Intelligence Techniques

Groundwater over-abstraction may cause land subsidence (LS), and the LS mapping suffers the subjectivity associated with expert judgment. The paper seeks to reduce the subjectivity associated with the hazard, vulnerability, and risk mapping by formulating an inclusive multiple modeling (IMM), which combines two common approaches of multi-criteria decision-making (MCDM) at Level 1 and artificial intelligence (AI) at Level 2. Fuzzy catastrophe scheme (FCS) is used as MCDM, and support vector machine (SVM) is employed as AI. The developed methodology is applied in Iran’s Tasuj plain, which has experienced groundwater depletion. The result highlights hotspots within the study area in terms of hazard, vulnerability, and risk. According to the receiver operating characteristic and the area under curve (AUC), significant signals are identified at both levels; however, IMM increases the modeling performance from Level 1 to Level 2, as a result of its multiple modeling capabilities. In addition, the AUC values indicate that LS in the study area is caused by intrinsic vulnerability rather than man-made hazards. Still, the hazard plays the triggering role in the risk realization.