Assessing urban drought vulnerability in northwest China using a social-ecological-technological framework

Drought poses incalculable risks to urban systems in arid areas. Water facilities, irrigation, and proprietary technologies play important roles in urban responses to drought disasters, but current vulnerability assessments ignore those technological factors. This study applied an interlinked social-ecological-technological systems (SETS) vulnerability framework by developing an urban drought vulnerability indicator system for 23 cities in Northwest China. Based on this framework, we calculated the spatial and temporal patterns of social, ecological, and technological vulnerability to urban drought separately and quantify the coupling coordination degree of the three. Then we used a random forest model to identify the key variables affecting the coupling coordination degree between social, ecological and technological system. The results show that the social and technological vulnerability to urban drought in Northwest China decreased significantly during the study period, but the ecological vulnerability did not decrease significantly. This suggests that ecological restoration as well as soil and water conservation measures should be taken to enhance urban ecosystem resilience to drought. The coupling coordination degree of social, ecological and technological vulnerability increased during the study period, indicating that integrated and synergistic SETS management should be taken to reduce the risk of drought. The key variables affecting the coupling of SETS vulnerability were the length of regional water supply pipes, wetland area, barren land area, population density, and sewage treatment capacity. Our study provides important decision-making information for regional drought disaster preparedness and response, and offers a new theoretical paradigm for drought vulnerability assessment in cities.