Abstract Rapidly growing cities in developing countries, including Kathmandu in Nepal, are struggling more and more to handle water issues brought by both urban growth and climate change. Conventional grey infrastructure is unable to manage rising problems of flooding, polluted water and a drop in groundwater recharge. This work evaluates how Green Infrastructure (GI) might help make Kathmandu Valley more sustainable and enhance ecosystem resilience through better water management. A mix of techniques was used, including analysis on GIS maps, river modeling, tracking field results of selected green technologies and semi-structured stakeholder interviews. GI interventions reduced surface runoff by up to 40%, improved water quality by reducing nutrient loads (BOD, nitrate, phosphate) by over 60%, and mitigated urban heat by 3-4°C. Spatial analysis identified priority zones for GI implementations are found along the Bagmati and in low-level urban areas through spatial analysis. Stakeholders reported widespread support from the public but say that much depends on the lack of coordination and the limited ability to maintain the lanes. The findings suggest that integrating GI a part of regular urban planning requires law changes, new funding sources and greater public participation. This research helps build the evidence for ecological adaptation and suggests useful steps to make the infrastructure in Kathmandu more resilient, livable, and ecological adaptive.