Coastal erosion, a worldwide social issue, has garnered substantial attention. Numerous methods have been implemented to control coastal erosion problems; however, the presence of rigid structures limits erosion mitigation, thereby causing various challenges. For instance, in the case of submerged breakwaters, local scour in front of the structure and scour caused by the flow occurring in open inlets affect the subsidence and stability of the structure and can also cause structural failure. To solve these problems, this paper proposes a hybrid method of using a submerged breakwater with an artificial coral reef installation; further, this study evaluates the attenuation of waves and mitigation of sediment transportation through large-scale 3D hydraulic experiments. We found that the hybrid method with an artificial coral reef installed in the open inlet shows excellent wave control and plays a clearly beneficial role in the advancement of the shoreline. The artificial coral reef method reduced the return flow generated by the drag force at the breakwater shoulder and open inlet. In addition, scour at the breakwater shoulder was inhibited by collecting the sand escaping offshore. Simultaneously, scour at the open inlet was also mitigated. The application of the hybrid method compensated for the problems caused by local scour and erosion in the submerged breakwater, thereby leading to the improvement of its function. Therefore, the hybrid method proposed in this paper was determined to be applicable not only for submerged breakwaters, but also for various structures for controlling coastal erosion.

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Analysis of the progression of forest fires is critical in understanding fire regimes and managing the risk of active fires. Major fire events in Korea mostly occur in the eastern mountainous areas (Gangwon Province), where the wind and moisture conditions are prone to fire in the late winter season. Despite the significance of the fire events in the area both in terms of frequency and severity, their spatial progression characteristics and their dependency on forest types have not been sufficiently analyzed so far, particularly with satellite data. This study first derived the severity map for the Uljin fire which occurred in March 2022, using a series of satellite images acquired over the fire period with very high frequency (every 5 days), and analyzed the characteristics of spatio-temporal progression in terms of forest types. The analysis revealed that the core fire area expanded very rapidly in the first few days, followed by an intensification phase that elevated severity in the active areas with marginal expansion in the peripheral areas. The analysis of the progression showed that the fire did not expand selectively by the forest type, despite the clear difference in their severity levels in the burned areas, where coniferous forest exhibited 3 times higher severity than deciduous forest.

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