ANALYSIS OF POTENTIAL IRRIGATION AREAS IN NAKHON SAWAN PROVINCE USING GEOGRAPHIC INFORMATION SYSTEM (GIS) AND ANALYTIC HIERARCHY PROCESS (AHP)

Abstract

This research aimed to: (1) assess the potential areas for irrigation development in Nakhon Sawan Province; (2) determine the weights of factors influencing irrigation potential using the Analytic Hierarchy Process (AHP); and (3) produce an irrigation suitability map by integrating the Geographic Information System (GIS) with the AHP technique. This study employed a spatial analysis approach using geospatial data obtained from the Land Development Department, the Royal Irrigation Department, the Department of Water Resources, and the Agri-Map database. Six criteria were considered in the analysis: land use, distance to water sources, slope, elevation, soil type, and average annual rainfall. The relative importance of these factors was determined using the Analytic Hierarchy Process based on the judgments of 15 experts. The derived weights were then integrated with GIS data through the Weighted Overlay technique to evaluate irrigation suitability. The results indicated that land use was the most influential factor, with a weight of 0.2784, followed by distance to water sources (0.2729), slope (0.2674), elevation (0.0759), soil type (0.0719), and average annual rainfall (0.0334). The pairwise comparison matrix achieved a Consistency Ratio (C.R.) of 0.084, indicating an acceptable level of consistency. The GIS-based suitability analysis revealed that 4,435,729.31 rai (77.00%) of the study area was classified as highly suitable (S1) for irrigation development, followed by unsuitable areas (N) accounting for 17.68%, moderately suitable areas (S2) accounting for 3.83%, and marginally suitable areas (S3) accounting for 1.49%. The findings demonstrate that integrating GIS with the Analytic Hierarchy Process provides a systematic and reliable approach for assessing irrigation potential. The resulting suitability map can serve as a valuable decision-support tool for irrigation planning, water resources management, and land-use planning, thereby enhancing agricultural productivity and promoting sustainable development in Nakhon Sawan Province.

Keywords: Irrigation Potential, Geographic Information System (GIS), Analytic Hierarchy Process (AHP), Irrigation Development, Nakhon Sawan Province