Framework development for the implementation of a nature-based solution in Lappeenranta

Urban stormwater management faces increasing pressure due to climate change and urbanization, which can intensify precipitation patterns and increase the risk of flooding. Nature‑based solutions (NBS) offer a sustainable alternative to traditional grey infrastructure, while providing additional ecosystem benefits. This thesis presents a multi‑criteria framework designed to identify suitable locations for implementing NBS for stormwater management in Lappeenranta, Finland. The framework includes a set of criteria and scenario‑based weighting, allowing the evaluation of thirty sites across the city. The results show that the most suitable areas were those capable of providing multiple benefits, such as reducing flood and sewer loads and strengthening green connectivity, rather than locations facing a single dominant challenge. A recently built nature-based solution in the city was also evaluated. Although it did not rank among the top sites, it is located near an area with stronger overall performance. The framework demonstrates strong flexibility and replicability and can support urban planners in prioritizing NBS locations to enhance urban resilience and sustainability.