Application of the Coastal Hazard Wheel methodology for coastal multi-hazard assessment and management in the state of Djibouti

AbstractThis paper presents the application of a new methodology for coastal multi-hazard assessment and management in a changing global climate on the state of Djibouti. The methodology termed the Coastal Hazard Wheel (CHW) is developed for worldwide application and is based on a specially designed coastal classification system that incorporates the main static and dynamic parameters determining the characteristics of a coastal environment. The methodology provides information on the hazards of ecosystem disruption, gradual inundation, salt water intrusion, erosion and flooding and can be used to support management decisions at local, regional and national level, in areas with limited access to geophysical data. The assessment for Djibouti applies a geographic information system (GIS) to develop a range of national hazard maps along with relevant hazard statistics and is showcasing the procedure for applying the CHW methodology for national hazard assessments. The assessment shows that the coastline of Djibouti is characterized by extensive stretches with high or very high hazards of ecosystem disruption, mainly related to coral reefs and mangrove forests, while large sections along the coastlines of especially northern and southern Djibouti have high hazard levels for gradual inundation. The hazard of salt water intrusion is moderate along most of Djibouti’s coastline, although groundwater availability is considered to be very sensitive to human ground water extraction. High or very high erosion hazards are associated with Djibouti’s sedimentary plains, estuaries and river mouths, while very high flooding hazards are associated with the dry river mouths

Conceptual hydrodynamic-thermal mapping modelling for coral reefs at south Singapore sea

YesCoral reefs are important ecosystems that not only provide shelter and breeding ground for many marine species, but can also control of carbon dioxide level in ocean and act as coastal protection mechanism. Reduction of coral reefs at Singapore coastal waters (SCW) region remains as an important study to identify the environmental impact from its busy industrial activities especially at the surrounding of Jurong Island in the south. This kind of study at SCW was often being related to issues such as turbidity, sedimentation, pollutant transport (from industry activities) effects in literatures, but seldom investigated from the thermal change aspect. In this paper, a computational model was constructed using the Delft3D hydrodynamic module to produce wave simulations on sea regions surrounding Singapore Island. The complicated semi-diurnal and diurnal tidal wave events experienced by SCW were simulated for 2 weeks duration and compared to the Admiralty measured data. To simulate the thermal mapping at the south Singapore coastal waters (SSCW) region, we first adapted a conversion of industrial to thermal discharge; then from the discharge affected area a thermal map was further computed to compare with the measured coral map. The outcomes show that the proposed novel thermal modelling approach has quite precisely simulated the coral map at SSCW, with the condition that the near-field thermal sources are considered (with the coverage area in the limit of 20 km × 20 km).The author also acknowledges the support of Nazarbayev University’s (Kazakhstan) research seed grant no. KF-12/6 for purchasing and providing the Delft3D software used in this study (which the author is the principal investigator of the grant

Coral Bleaching Data

Coral bleaching is a major phenomon affecting coral reefs around the world. An initial database of bleaching observations was compiled by UNEP-WCMC using a variety of sources. This database has been expanded by Dr. J. Oliver, Mr. Y. Yusuf and Ms. Nurulhuda Ahmad Fatan from WorldFish, using information from the ReefBase database, the Great Barrier Reef Marine Park Authority (GBRMPA), the CoralList, and other sources of information. This dataset also includes observations indicating no bleachin

Fishers perceptions of ecosystem service change associated with climate-disturbed coral reefs

Understanding ecosystem service change necessitates an understanding of the social and ecological dimensions of ecosystem services and how they contribute to the well-being of different people. These empirical research gaps persist across the tropics and in coastal environments, posing a challenge for small island states that depend on ecosystem services associated with near-shore ecosystems like coral reefs. Perception-based approaches allow for a rapid appraisal of what constitutes ecosystem service change, providing insights into why these changes matter, and how experiences of change differ between individuals. To capture perceptions of change in four ecosystem services associated with coral reefs (habitat, fishery, coastal protection and recreation services), we conducted 41 semi-structured interviews with coral reef fishers from Seychelles, where reef ecosystems have been severely impacted by climate disturbance. We gathered quantitative and qualitative data to understand (a) if and what changes in reef-associated ecosystem services have been perceived; (b) if fishers’ characteristics are associated with differences in perceived changes and (c) which changes matter most in fishers’ lives. Using a three-dimensional approach to well-being, we sought to identify whether reasons behind the importance of change connect to fishers’ well-being. There have been noticeable changes across all four ecosystem services investigated. Changes include social, ecological and behavioural dynamics. Every fisher perceived at least one ecosystem service change but fishers who dive/snorkel or work from larger boats perceived a higher number of ecosystem services to have changed. Education, age and participation in snorkelling/diving were associated with fishers who identified changing habitat services as most important, whereas fishers from families with fewer livelihood alternatives and from smaller islands identified changing fishery services as most important. Different aspects of the subjective, relational and material dimensions of well-being were implicated in why changing services matter. Despite known ecological shifts in reef condition, this research is one of few studies to empirically show how changes across multiple ecosystem services are being perceived. These perceived changes are complex, engage both the social and ecological dimensions of services, and connect in multiple ways to how fishers feel about their lives, their relationships and material well-being. A free Plain Language Summary can be found within the Supporting Information of this article