GIS-Based Environmental Vulnerability Mapping in Terrebonne Parish, Louisiana

Coastal environments are increasingly exposed to environmental degradation and climate-related hazards driven by sea-level rise, land subsidence, and ecosystem deterioration. Identifying spatial patterns of environmental vulnerability is therefore essential for effective coastal management and climate adaptation planning. This study evaluates environmental vulnerability zones within the bayou ecosystems of Terrebonne Parish, Louisiana, using a Geographic Information System (GIS)–based Spatial Multi-Criteria Analysis (SMCA) integrated with the Analytical Hierarchy Process (AHP). Seven key environmental indicators, temperature, precipitation, Normalized Difference Vegetation Index (NDVI), Normalized Difference Moisture Index (NDMI), relative humidity, elevation, and slope were analyzed to capture the climatic, ecological, and topographic drivers of vulnerability. Satellite-derived datasets, digital elevation models, and climate observations were integrated within ArcGIS to generate spatial factor maps for each variable. AHP was applied to determine the relative importance of the environmental indicators through pairwise comparisons, enabling systematic weighting of criteria within the vulnerability model. The resulting weighted overlay analysis classified Terrebonne Parish into five vulnerability zones: very low, low, moderate, high, and very high risk. Results indicate that approximately 47% of the parish falls within high to very high vulnerability zones, primarily concentrated in the southern and southeastern coastal areas characterized by low elevation, degraded vegetation, and strong exposure to coastal hazards. In contrast, northern areas exhibit relatively lower vulnerability due to higher elevations and more stable environmental conditions. The study demonstrates that integrating GIS-based spatial analysis with AHP provides a transparent and effective framework for assessing environmental vulnerability in complex coastal landscapes where data limitations and multiple interacting variables complicate decision-making. The vulnerability maps generated in this study provide valuable information for environmental planning, wetland restoration, and climate adaptation strategies in coastal Louisiana. The findings highlight the importance of incorporating spatial decision-support tools into coastal management policies to enhance ecosystem resilience and reduce climate-related risks.