# Evaluation of Green and Grey Flood Mitigation Measures in Rural Watersheds
## 5 Conclusions  
This paper presents a comprehensive, micro-scale flood damage assessment under various scenarios of flood mitigation in a predominately rural, agricultural watershed. The objective of this research is identification of optimal flood protection setup that would result in maximum benefits, i.e., reduction of losses due to floods in such watersheds. Considering a relatively small body of research on this topic up to date, especially on valuation of damages to agricultural assets [41], and considering impacts that flood mitigation in rural watersheds can have on downstream urban areas [34], this paper presents an effort to fill this gap and provide a contribution to a better understanding of flood risk assessment and management in general. It is demonstrated that the detention basins, as an example of green flood mitigation measures that reduce peak flood flows in downstream river sections, can significantly decrease flood hazard in rural, agricultural watersheds. In the case of the Tamnava watershed, this peak flow reduction is sufficient to enable the existing system of protection levees to operate without failure and accept design floods without overtopping. On the other hand, heightening of levees, as an example of grey flood protection measures, increases flood protection locally, but with the potential of transferring some of the flood hazard further downstream. Unlike urban watersheds, in which high-priced assets are localized in relatively small areas, rural watersheds are characterized by larger areas and long river banks that would require long and excessively expensive levee systems. Additionally, since the crops are the most valuable assets in rural watersheds, flood losses to agriculture represent a great portion of total losses in such areas, as demonstrated by a fine-scale detailed damage assessment in this paper. Therefore, with the assets distributed across large areas in rural watersheds with significantly lower asset values per unit area than in urbanized watersheds, grey flood protection measures such as the levees cannot be as effective in reducing flood risk as the green measures reducing peak flows in rural watershed, as shown in this research. This paper confirmed that hybrid-type flood mitigation setups, i.e., combining large-scale, far-reaching green mitigation solutions that reduce peak flood flows with the existing smaller scale grey flood protection measures, can be the most effective solution for rural watersheds with prevalent agricultural land use and production. **Supplementary Materials:** The following are available online at [[http://www.mdpi.com/2076-3417/10/19/6913/s1](http://www.mdpi.com/2076-3417/10/19/6913/s1)]([http://www.mdpi.com/2076-3417/10/19/6913/s1](http://www.mdpi.com/2076-3417/10/19/6913/s1)). **Author Contributions:** Conceptualization, R.P. and J.P.; methodology, R.P., J.P. and A.T.; software, R.P. ; validation, J.P., A.T.; formal analysis, data curation, R.P. ; investigation, R.P., J.P. and A.T.; writing--original draft preparation, R.P. ; writing--review and editing, R.P., J.P. and A.T.; visualization, R.P., J.P.; supervision, J.P.; project administration, J.P. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by University of Belgrade - Faculty of Civil Engineering as a part of a PhD research activities. Data collection was funded from the European Union's Horizon 2020 Research and Innovation programme under grant agreement No 776866 for the RECONECT (Regenerating ECOSystems with Nature-based solutions for hydro-meteorological risk ErGluCTion) project. The study reflects only the authors' view and the European Union is not liable for any use that may be made of the information contained herein. **Acknowledgments:** The authors would like to thank the staff of Public Water Management Company \"Sfbijavode\", Belgrade, Serbia, for providing various documentation and information and for their assistance with field visits.