| Abstract | Urban water and sanitation systems are increasingly vulnerable to climate change, rapid urbanization, and growing service demands, placing substantial pressure on infrastructure performance, water availability, and long-term service reliability. In many rapidly growing cities, these pressures contribute to recurring flooding, water shortages, and operational disruptions. Khon Kaen City, a secondary city in Thailand, represents one such case where increasing climate variability and urban growth are intensifying risks to urban water and sanitation systems. Despite these challenges, practical and integrated approaches for assessing climate resilience in secondary-city water and sanitation systems remain limited.This study aimed to assess the climate resilience of the urban water supply and sanitation system in Khon Kaen using an index-based multi-criteria resilience assessment framework. The framework was developed through literature review, expert consultation, and Analytical Hierarchy Process (AHP) weighting. The assessment incorporated three key dimensions: Climate Stressors (D1), Infrastructure Operations (D2), and Quality of Service (D3). Historical climate trends and future climate projections under SSP2-4.5 and SSP5-8.5 scenarios were analyzed to evaluate future climate pressures and their implications for urban water and sanitation management.The findings indicate that the overall resilience of the urban water supply and sanitation system in Khon Kaen is at a good level, with an overall resilience index of 3.37. However, important operational and infrastructure-related weaknesses remain. The Climate Stressors dimension achieved a good resilience score (D1 = 3.48), suggesting that the system is currently capable of managing existing climate-related pressures. Similarly, the Quality-of Service dimension showed strong performance (D3 = 3.68), reflecting relatively reliable service delivery. In contrast, Infrastructure Operations was identified as the weakest dimension (D2 = 2.92), highlighting critical limitations in system redundancy, wastewater treatment performance, sewer inspection and maintenance practices, and decentralization capacity. The analysis further revealed that increasing temperature stress and future rainfall variability may intensify pressure on existing infrastructure and treatment operations, particularly in areas already showing low resilience performance. These findings suggest that while current services remain functional, the system’s long-term adaptive capacity may be constrained without targeted operational and infrastructure improvements.Based on the identified resilience gaps, the study evaluated adaptation strategies through multi-criteria prioritization and scenario-based analysis. The results demonstrated that integrated approaches combining infrastructure upgrades, operational strengthening, climate adaptive planning, and institutional coordination provided the greatest improvement in overall system resilience compared with isolated interventions. The study provides a practical and transferable framework for supporting climate-resilient urban water and sanitation planning in rapidly growing secondary cities facing increasing climate uncertainty. |
