A geographic information system-based socioeconomic impact assessment of the broadening of national highway in Sikkim Himalayas: a case study

Socioeconomic impact assessment (SEIA) is an undermined area of environmental impact assessment of highway projects. The problem becomes even more pronounced in remote and difficult terrains. The challenge in data gathering and impact prediction in mountainous areas can be mitigated using Geographic Information System (GIS). In this paper, an attempt has been made to apply the techniques of GIS and Analytic Hierarchy Process (AHP) to perform a rapid SEIA on broadening of national highway in a mountainous terrain like Sikkim. The proposed spatial impact model shows the distribution of impacts of highway broadening on socioeconomic attributes and generates a composite impact inventory map. The composite impact is found to be slightly to moderately beneficial for the study area. Cross-validation of Empirical Bayesian Kriging (EBK) and sensitivity analysis have also been carried out for model evaluation. Cross-validation results show a reliable spatial interpolation. Sensitivity analysis shows a robust decision model and identifies the socioeconomic attributes to which the spatial impact model is sensitive. The study presents a novel methodology of rapid spatial SEIA.