Assessment of Optimal Route Selection for Roads Construction Using Geospatial Technologies: A Case of Dembidollo - Mettu, Oromia, Ethiopia

Abstract

The absence of a direct and well-maintained road between Dembidollo and Mettu towns in the Oromia Zones of Ethiopia resulted in prolonged travel times, increased costs, and hindered movement. This study aimed to utilize geospatial technologies to select the best route alignment that would efficiently connect the two towns. Through geospatial analysis, a suitable route alignment was identified, and the economic, technical, and environmental aspects of the proposed alignments were evaluated. High-resolution Digital Elevation Model (DEM) data and Sentinel 2A imagery were employed for generating slope, elevation, drainage order, and land use and land cover (LULC) classification. Data processing and analysis were conducted using geospatial software such as ArcGIS, ENVI, Idrisi Selva, Global Mapper, and Google Earth. A systematic method was followed, encompassing data collection and processing, criteria prioritization using the Analytical Hierarchy Process, weighted overlay of thematic maps, least cost path generation, and evaluation based on preferred theme maps. The analysis emphasized the significance of economic factors in route selection, giving the highest weight to the economically preferred least cost path. The findings demonstrated a substantial improvement offered by the proposed route alignment, resulting in a remarkable distance reduction from 271 km to 96.46 km. The recommended route alignment proved to be cost-effective, safe, and resilient by avoiding higher-order drainage and minimizing disruptions. Adoption of this route alignment was recommended, as it would bring benefits such as reduced travel costs and time, improved community services, enhanced economic opportunities, and affordable transportation of goods. In conclusion, the effectiveness of geospatial technologies and multi-criteria evaluation methods in selecting the optimal road route alignment is showed. The integration of remote sensing and GIS proved highly efficient and cost-effective for large-area imaging. By considering multiple parameters and incorporating multi-criteria evaluation, a comprehensive assessment of the proposed alignments was achieved, highlighting the practicality and effectiveness of geospatial technologies in road infrastructure development. These insights provide valuable guidance for future studies and contribute to the development of economically viable and sustainable transportation networks.