Using a Smart City framework that focuses on connectivity, Nature-based Solutions, and community well-being supported by ICT, I discuss the successes, challenges, and opportunities to re-image our approach to urban water management by better integrating landscape architecture and urban design with mathematical modelling. The modelling includes both conceptual, dynamic hydrologic modelling and evaluation of ecosystem services. This approach requires effective multidisciplinary collaboration rather than traditional silo-thinking that too-frequently remains the hallmark of university programs today. I focus principally on outcomes from our recently completed Thammasat-Nava Nakorn Smart District study in Thailand, but also draw on case studies from water projects in Singapore, Cambodia, and Australia. Pressures of urbanization on water systems in Southeast Asia are enormous. What happens when they fail?