Benefits of Green Infrastructure for Flood Mitigation in Small Rural Watersheds—Case Study of the Tamnava River in Serbia

Abstract

A consideration of climate change in recent years shifted the focus on re-evaluation of classical flood protection measures in riverine systems. While the conventional, grey infrastructure measures have their established role, an emergence of green, eco-friendly measures has been increasingly evaluated. Understandably, due to space and capacity limitations, green measures have been applied and studied primarily in urban areas. Recently, the importance of green infrastructure has been highlighted as an effective flood-fighting methodology in rural areas as well. This paper focuses on evaluation of various conventional and nature-based scenarios in reducing flood risk in small, rural watersheds. Mitigation effectiveness (loss reduction) is evaluated using a robust, micro-scale economic model, which compares direct flood damages and indirect losses for four sets of conditions: 1) Existing flood protection system (baseline); 2) Flood protection using enhanced grey infrastructure; 3) Protection system using nature-based solutions; and 4) A combination of grey and green infrastructure. The evaluation considered not only direct damages to structures and crops, but included indirect losses related to population displacement and relocation. The preliminary results demonstrated that the most effective flood loss reduction is achieved using an integrated combination of both types of infrastructure, with emphasis on large-scale (watershed scale) nature-based solutions. While the research at this stage provided valuable guidelines, further study is planned on quantifying ecosystem functions value on the watershed level and their long-term improvement using nature-based solutions.