Geophysical-Geotechnical Evaluation of Site Suitability Assessment of Roads in Mountainous and Rugged Terrains Using a GIS-MCE Approach: A Case Study of Simbu Province, PNG

Abstract

The rugged topography of Papua New Guinea (PNG) makes it a challenge for the government to extend standard road infrastructure in the remote and mountainous parts of the country. Although road construction is one of the priority investments by government in recent times, public infrastructure objectives are not met due to technical and financial challenges. The performance of the road network in Simbu Province of the Highlands Region is a serious concern particularly with regard to poor connectivity, poor accessibility and constant failing of serviceable roads due to their difficult geography at the landscape level. This study seeks to develop a site suitability model for evaluating technical requirements of roads in difficult terrains and mountainous areas using GIS and multi-criteria evaluation (MCE) approach through Analytic Hierarchy Process (AHP). Towards this end, the paper classifies geophysical-geotechnical influences as principal factors determining road suitability. Comparatively important geophysical factors, including altitude, slope, river network and rainfall data, are integrated to generate alternative suitability Map 1. Geotechnical factors including lithology, soil texture and landform are integrated to generate alternative suitability Map 2. The final suitability map is produced by combining both weighted composite map layers in order to identify the most suitable site in a cost-effective, environment-friendly and well organised manner.