Evaluation of Green and Grey Flood Mitigation Measures in Rural Watersheds

Ranko Pudar,Andrijana Todorović,Jasna Plavšić

doi:10.3390/app10196913

Abstract

Floods cause considerable damages worldwide and mitigation of their adverse effects through effective protection measures is needed. Along with the commonly applied “grey” infrastructure, “green” measures that can offer additional benefits, such as ecosystem services, are increasingly being considered lately. While the recent research tendencies are focused on the effectiveness and the value of green measures in urban areas, this paper presents a comprehensive financial evaluation of green and grey flood mitigation scenarios for a smaller rural watershed. A micro-scale damage model that builds on the hydrodynamic modeling of hazard, detailed asset identification, and damage assessment is presented and applied for evaluation of benefits from various flood mitigation measures in the Tamnava watershed in Serbia. Four scenarios are considered: (1) existing flood protection system; (2) green scenario involving new detention basins; (3) grey infrastructure enhancement by rising of the existing levees and diverting flood discharges; and (4) green-grey scenario that combines scenarios (2) and (3). The benefits (loss reduction) are the greatest with the green scenario and marginally higher with the combined green-grey scenario. The results suggest that for small rural watersheds, a holistic, integrative approach that includes both types of infrastructure can provide the most effective flood risk mitigation.

Highlights

State and municipal governments are facing depleting natural resources, adverse climate change impacts, and many socio-economic challenges
The share of agricultural damages in total losses depends on local conditions in the watershed [34] and prevalence of higher-value crops [41], the results presented here clearly indicate that the agricultural damages are not marginal and have a critical impact on the selection of flood protection development scenarios in predominately agricultural watershed
This paper presents a comprehensive, micro-scale flood damage assessment under various scenarios of flood mitigation in a predominately rural, agricultural watershed

Summary

Introduction

State and municipal governments are facing depleting natural resources, adverse climate change impacts, and many socio-economic challenges. Despite being essential for economic growth, these infrastructure investments are significant and continue throughout the life of any such project, through annual maintenance costs [1]. This point is of particular importance in infrastructure designed to provide protection from natural hazards, and flood hazards. Large drainage systems and structural flood protection are being exposed to natural decay and require constant investment. They are characterized by a limited life span and declining benefits and are under additional stress by the changing climate [2,3]. Grey infrastructure has a very limited role in ecosystem functions and can lead to degradation of local and regional systems [3]

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