Urban rivers in India, particularly those in delta-influenced catchments, are experiencing rapid ecological decline due to uncontrolled urban expansion, pollution, and fragmented governance. This study explores nature-based solutions (NbS) as effective strategies not only for rehabilitating the Harmu River in Ranchi, Jharkhand—a small urban stream with delta-like features—but also for advancing broader objectives of sustainable urban development and climate resilience. It examines potential interventions such as riparian buffer planting, decentralized stormwater management systems (e.g., bioswales and rain gardens), floodplain wetland restoration, and the creation of multifunctional public green spaces to revitalize riverine ecosystems and provide socio-ecological co-benefits. The methodology involves spatial mapping, environmental assessment, policy review, and stakeholder consultations to develop an integrated NbS framework tailored to specific local conditions and needs. Particular emphasis is placed on community-based adaptation practices and inclusive governance mechanisms to foster long-term stewardship of the river corridor. The study also considers how these interventions align with relevant United Nations Sustainable Development Goals (particularly SDG 6 on clean water and sanitation, SDG 13 on climate action, and SDG 11 on sustainable cities). This work contributes to the growing research on ecosystem-based disaster risk reduction, climate adaptation, and urban river resilience in India’s smaller cities. By treating the Harmu as a pilot case for applying NbS in compact urban delta settings, the study aims to bridge scientific design with participatory implementation. The findings are expected to inform policy recommendations for integrating NbS into urban planning and river basin governance frameworks, thereby actively supporting India’s transition toward more resilient, sustainable, and livable deltaic landscapes at large.