Efficient Integration of Water Demand using Fuzzy Analytical Hierarchical Process Model with Geographic Information System in Vientiane Capital, Lao PDR

Abstract

Water demand management remains a critical challenge in rapidly urbanizing cities, particularly in Southeast Asia where infrastructure expansion often lags behind demographic growth. This study develops an integrated framework that combines the Fuzzy Analytic Hierarchy Process (FAHP) with Geographic Information System (GIS) to analyze domestic water demand in Vientiane Capital, Lao PDR. Five criteria consist of population density, household size, access to piped water, distance from water sources, and elevation were evaluated through expert-based pairwise comparisons using FAHP, which effectively addresses uncertainty and subjectivity in decision-making. The derived weights were incorporated into spatial datasets and analyzed using the Weighted Overlay technique in ArcGIS Pro to generate a Water Demand Suitability Map. Quantitative results classified water demand into five levels: very high (4.40%), high (60.11%), medium (7.34%), low (8.79%), and very low (19.36%). High and very high demand zones were concentrated in the urban core districts Chanthabouly, Xaisettha, Sikhotabong, Sisattanak, and Hatxayfong. These areas host most water treatment plants, piped distribution systems, and economic activities. In contrast, medium- to very low-demand areas were found in peripheral districts such as Sangthong, Naxaythong, Xaithani, and Pakngum, where approximately 20% of villages lack piped water access and seasonal droughts exacerbate water scarcity.  Access to piped water (weight = 0.503) and population density (weight = 0.231) emerged as the most influential determinants, underscoring the importance of infrastructure and demographic pressures in shaping demand. The novelty of this study lies in extending FAHP-GIS applications from hazard and drought assessments to domestic water demand analysis, thereby providing a replicable tool for prioritizing infrastructure investment and resource allocation. Limitations include reliance on expert judgment for weighting and the exclusion of climate change projections, which should be addressed in future research. Overall, the integrated FAHP-GIS approach offers a practical and innovative decision-support framework for policymakers and water authorities to design resilient strategies for sustainable water resource management under conditions of rapid urbanization and climate variability.