The north coast of Java Indonesia is an area threatened by erosion due to rising sea levels triggered by climate change. Sayung District, Demak, which experienced severe erosion impacts. Restoring lost sediment is an effective way to stop erosion processes and restore a stable coastline. In this chapter, the strategies of coastal protection carried out are presented with the ultimate goal of restoring the natural defense of the coast, namely, mangroves. The first step is to build a coastal protective building to reduce waves and create calm waters. It will accelerate the sedimentation process so that new sludge-substrate land will be formed that is suitable for mangrove ecosystem growth. This coastal erosion mitigation activity is an effort to increase the resilience of coastal areas from physical aspects that cause deterioration or reduction of coastal functions. The concept of building together with nature has a very high technical, socioeconomic, and environmental feasibility because it is a coastal engineering approach as one of the solutions to the problem of sustainable erosion.

Timbulsloko is a village on the coast of Sayung District, Demak Regency that is severely affected by coastal erosion. The coastal erosion in the Timbulsloko Village is mainly caused by the removal of mangrove areas, which has eliminated the function of the natural breakwater for the coast of the Timbulsloko Village. This study aimed to mitigate the coastal erosion in the form of structural and non-structural protection. Structurally (physically), mitigation is conducted by protecting the coastal area with the application of environmentally friendly coastal protection technology in the form of a Permeable breakwater with a Hybrid Engineering structure. Furthermore, the effectiveness of two different structure segments in damping waves from September 2020 -March 2021 will be measured. In contrast, non-structurally, mitigation is conducted in a non-physical way by analyzing the Coastal Vulnerability Index of Timbulsloko Village based on the parameters of Coastal Typology, Average Tidal Range, Significant Wave Height, Coastal Slope, Coastal Geomorphology, Sea Level Rises, and Shoreline Displacement using the CVI method. The effectiveness of the permeable structure's wave damping is determined by the initial wave height and transmission wave height measured by the ultrasonic sensor. On the basis of segment differences, the Permeable Breakwater Segment 2 with a distance between bamboo of 0.25 m has better effectiveness than a Permeable Breakwater Segment 1 with a distance between bamboo of 0.5 m. The results of the Coastal Vulnerability Analysis show that the Timbulsloko Village is vulnerable to coastal disasters, especially coastal erosion.