Coastal management based on multi-hazard assessment in the very small islands of Karimunjawa, Indonesia

Small islands are particularly vulnerable to climate change risks due to their geographical isolation from the mainland and limited resources. The development of coastal areas can efficiently address socio-economic and environmental objectives. An illustration of this is the coastal areas located on various small islands within the Karimunjawa Islands, which have attained considerable popularity among tourists. This study aims to analyze the distribution of multi-hazards arising from climate change and identify a suitable coastal environmental management strategy for implementation on the small islands of Karimunjawa. The variables encompass landform, wave exposure, tidal range, coastal ecosystems, sediment equilibrium, and storm climate. The findings reveal that the majority of coastal areas in Karimunjawa's small islands exhibit a moderate level of ecosystem disruption and coastal erosion, whereas the lower level includes gradual inundation, seawater intrusion, and coastal flooding. The elements of landform and sediment balance substantially influence the multi-hazard classification in this area. Coastal areas situated on steep landforms with a surplus of sediment typically exhibit a low multi-hazard classification, and vice versa. Possible management strategies to alleviate the impacts of ecosystem disruption encompass coastal zoning, ecosystem-based management, and inaction. Adopting a "do nothing" management strategy also effectively alleviates the effects of gradual inundation and coastal flooding. Also, using management strategies like growing Scaevola taccada and combining mangroves with structures that protect the coast can greatly lessen the effects of coastal erosion on areas that are more likely to be affected. If adequate resources are available, we can implement alternative management strategies such as the construction of seawalls, dikes, or revetments combined with breakwaters.