Jun Sasaki’s Lab

Main research themes

1. Assessment of the Co-Benefits of Structures in Coastal Areas for Tsunami Mitigation and Improving Community Resilience in Sri Lanka

Sameera Samarasekara

Description

A quantitative analysis of the co-benefits that structures in coastal communities can have to enhance tsunami disaster resilience is essential to identify the most economical disaster mitigation measures. This research assesses the contribution of a revetment and a coastal railway embankment for enhancing the resilience against tsunamis of two coastal villages (Dimbuldooa and Wenamulla) along the southwestern coast of Sri Lanka. The tsunami mitigation co-benefit of those structures has been presented in monetary terms by equating it to the expected amount of damage that they could prevent from happening. This assessment was carried out through numerical simulations of possible tsunamis which can result from tsunamigenic earthquakes with return periods of between 100 and 1500 years originating in the Andaman zone of the Sunda subduction zone. The results reveal that both types of existing structures have a tsunami mitigation co-beneficial function. However, they might require slight upgrading in order to ensure that they do not suffer significant damage and collapse during the successive waves that form part of a tsunami. Furthermore this research assesses resident’s willingness to pay (WTP) for hard defensive measures, as well as the socioeconomic factors that influence residents’ WTP. WTP of residents to upgrade a coastal railway embankment and a revetment in Dimbuldooa and Wenamulla villages was measured by conducting a structured questionnaire survey of 200 residents. The results of the survey were triangulated through five expert interviews with representatives of government agencies, construction companies and academia, and two focus group discussions with residents. The findings suggest that it is necessary for disaster risk managers to pay special attention to socioeconomic factors to successfully enhance the resilience of community. The findings suggest that it is necessary for disaster risk managers to pay special attention to socioeconomic factors to successfully enhance the resilience of community.

Conducting a focus group discussion with female leaders in Dimbuldooa and wenamulla

Conducting an interview with Government officers in Coast Conservation and Coastal Resource Management Department

Publications

R.S.M. Samarasekara, J. Sasaki, M. Esteban, H. Matsuda, Assessment of the Co-Benefits of Structures in Coastal Areas for Tsunami Mitigation and Improving Community Resilience in Sri Lanka, Int. J. Disaster Risk Reduct. (2017). https://doi.org/10.1016/j.ijdrr.2017.04.011.

R.S.M. Samarasekara, J. Sasaki, M. Esteban, H. Matsuda, Willingness to Pay for Upgrading Tsunami Co-Beneficial Structures: Example from A Railway Embankment and A Revetment in Sri Lanka, The 9th International Conference on Asia and Pacific Coasts 2017 (APAC 2017) SMX Convention Centre, pp 139-149, Pasay City, Philippines, 19th – 21st October 2017, https://doi.org/10.1142/9789813233812_0014

Special awards

“Excellent Presentation Award”, for researchers below 36 years old, at the annual symposium of Japanese Association for Coastal Zone Studies, held back in July, in Kochi, Japan, 2016. Presentation title was Assessment of Contribution of Upgraded Coastal Infrastructure for Tsunami Mitigation: Improving Community Resilience in Developing Coastal Regions

 

2. Perspectives on Coastal Erosion: A Integral Approach to Historical Changes in Social Systems and Shoreline Management in Marawila Beach of Sri Lanka from 1980 – 2017

Sameera Samarasekara

Description

Erosion of sandy coasts brings a serious hazard to life and properties in coastal regions. Various engineered coast protection solutions are immediately introduced to stabilize threatened coasts without completely knowing the fundamental causes of erosion and upcoming sustainability impacts of solutions which can potentially influence the socio-economic and environmental process in various forms. However a methodological framework to introduce a sustainable solution based on different coast users’ opinions and impacts of immediately introduced coast protection measures has been not introduced yet. This study aims to develop a methodological framework by interpreting a case study empirically via well-established methodologies of coastal engineering, economics and sociology. However this abstract presents a chronological review of coast protection (Government responses) Key informant interviews were conducted with Government officers, academia and fishing unions in order to identify Government responses, stakeholders’ perceptions of possible causes of erosion and solutions. Furthermore we administered questionnaires with owners of damaged (and threatened) houses, hotel owners and fishermen while walking along the coastline and workers at sand mining sites while travelling towards upstream from Maha River estuary. Chronological evolution of shoreline since 2003 was analyzed from available satellite images (flowed by a GIS analysis) and current images of coastline which were obtained from a drone (DJI® Phantom 3 – Professional) in February, 2017 and August, 2017. A bathymetric survey was carried out from sonar attached to a small fishing boat as such data are limited. Furthermore we fixed a Brinno ® camera at river mouth to visually inspect the shoreline changes. This study aimed to recognize historical changes in coastal system of Marawila Beach from 1987 to 2017 related to shoreline management as a developing country. The study discusses the methodical results and their inter-relatedness in physical perspectives, social perspectives, personal perspectives and cultural perspectives by using integral framework.

Figure 4: Conducting a bathymetric survey from sonar attached to a small fishing boat

Figure 5: Fixing a Brinno® camera to observe the changes in Maha River mouth

3. Evaluation of Groundwater Quality, Social Health Vulnerability and Population Mobility Tendency in the South-Western Coastal Region of Bangladesh

RAKIB Md Abdur

Description

My research focuses on the groundwater contamination and its associated social health and population mobility issues in the southwestern part of Bangladesh. On account of, Bangladesh is a low-lying deltaic and disaster-prone country. Climate change impacts are apparently serious in the coastal part because of sea level rise, cyclonic storm surges, tidal riverbank erosion, waterlogging and saltwater intrusion. Nowadays, water and soil salinity increases than the previous level. Nevertheless, scarcity of drinking and irrigation water is noticeable and serious threats while a large number of people live in poverty. However, this research will be helpful to identify the cause of coastal hazards like the salinity intrusion and social crisis alongside sustainable measures.

 

4. Evaluating the Sustainability of a Marine Protected Area: The case of El Nido-Taytay Managed Resource Protected Area

Avelino, John Erick

Description

The Philippines has established Marine Protected Areas throughout the country and it has been regarded as an important component of coastal resource management (Alcala, 1998). Currently, a total of 1,620 MPAs were already established, however, there is still the need to improve the management effectiveness of these MPAs. In order to improve management of the MPAs, the study tries to integrate natural science and social science research to come up with a holistic understanding on the impacts of the existing threats to coral reefs, its implication to the coastal community, and analyze the appropriateness of the management interventions currently undertaken by the Protected Area. The study conducted: 1) Dive Surveys using the Reef Check method to assess the coral reef cover; (2) Household Surveys to determine the Knowledge, Attitude and Perception of the Coastal Community; and (3) Key Informant Interviews, and the application of the Management Effectiveness Assessment Tool (MEAT) to determine the governance within the Protected Area.

Deployment of the transect line for the coral reef survey

 

Conduct of the household survey for coastal communities