Development of Disaster Mitigation Approach and Coastal Area Carrying Capacity Based on Coastal Vulnerability Index (CVI): A GIS Analysis in Betahwalang Waters, Demak

Abstract

This study aims to develop an integrated framework for disaster mitigation and coastal carrying capacity assessment by combining the Coastal Vulnerability Index (CVI) with trophic status analysis in Betahwalang Waters, Demak. Unlike previous studies that primarily evaluate physical vulnerability or ecological conditions separately, this study integrates both approaches to identify areas where high physical susceptibility coincides with ecological pressure, thereby providing a more comprehensive basis for sustainable coastal management. Seven physical parameters, including geomorphology, slope, elevation, land use, distance from the shoreline, distance from rivers, and tidal range, were analyzed using a weighted overlay approach in ArcGIS based on field observations, Sentinel-2 imagery, Digital Elevation Model (DEM), and tidal data. Ecological carrying capacity was assessed using trophic status derived from chlorophyll-a and nitrate concentrations following the EPA trophic classification. The results indicate that 69.01% of the study area falls within the high (42.96%) and very high (26.05%) coastal vulnerability classes, primarily due to low elevation, gentle slopes, and extensive aquaculture replacing natural mangrove protection. Chlorophyll-a concentrations ranged from 2.19 to 36.19 µg.L^-1, while nitrate concentrations ranged from 43.62 to 126.52 µg.L^-1, indicating mesotrophic to eutrophic conditions with moderate to high nutrient enrichment. The integrated assessment revealed that physically vulnerable areas generally coincide with nutrient-enriched coastal waters, indicating increasing environmental pressure and reduced ecological carrying capacity. These findings demonstrate that integrating CVI with trophic status provides additional spatial insight beyond conventional vulnerability assessments by simultaneously identifying priority areas for ecosystem restoration, disaster risk reduction, and sustainable aquaculture management. The integration of CVI and trophic status provides additional spatial insight by identifying areas where high physical vulnerability coincides with ecological pressure, thereby supporting ecosystem-based disaster mitigation and sustainable coastal management. The proposed framework supports evidence-based coastal planning through ecosystem-based disaster mitigation strategies, including mangrove restoration, spatial zoning, and adaptive coastal management under climate change.