Exploring Options for Flood Risk Management with Special Focus on Retention Reservoirs

Nejc Bezak,Simon Rusjan,Gregor Johnen,Andrej Vidmar,Martina Kovačević,Klaudija Lebar,Vesna Zupanc

doi:10.3390/su131810099

Nejc Bezak, Simon Rusjan + Show 5 more

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https://doi.org/10.3390/su131810099

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Abstract

Floods are among the most frequent and deadliest natural disasters, and the magnitude and frequency of floods is expected to increase. Therefore, the effects of different flood risk management options need to be evaluated. In this study, afforestation, permeable concrete implementation, and the use of dry and wet retention reservoirs were tested as possible options for urban flood risk reduction in a case study involving the Glinščica river catchment (Slovenia). Additionally, the effect of dry and wet reservoirs was investigated at a larger (catchment) scale. Results showed that in the case of afforestation and permeable concrete, large areas are required to achieve notable peak discharge reduction (from a catchment scale point of view). The costs related to the implementation of such measures could be relatively high, and may become even higher than the potential benefits related to the multifunctionality and multi-purpose opportunities of such measures. On the other hand, dry and wet retention reservoirs could provide more significant peak discharge reductions; if appropriate locations are available, such reservoirs could be implemented at acceptable costs for decision makers. However, the results of this study show that reservoir effects quickly reduce with scale. This means that while these measures can have significant local effects, they may have only a minor impact at larger scales. We found that this was also the case for the afforestation and permeable concrete.

Highlights

Floods are natural disasters that can cause large economic damage and endanger human lives [1,2,3,4]
The results showed that in the case of afforestation and permeable concrete implementation, relatively large areas are needed in order to achieve notable peak discharge reduction or a shift in peak discharge timing and a corresponding impact on flood risk reduction
It was shown that the impact of dry and wet retention reservoirs reduced with scale depending on the size of the retention reservoirs, which means that such measures often have a local impact

Summary

Introduction

Floods are natural disasters that can cause large economic damage and endanger human lives [1,2,3,4]. The magnitude and frequency of floods are expected to increase in many parts of world in future decades due to climate change [5,6,7,8]. The seasonality of floods is changing throughout the globe [9]. Different structural and non-structural measures will inevitably need to be implemented to cope with the increasing flood risk [10,11,12]. Flood forecasting can be one of the solutions to warn people living in flood hazard areas [13,14,15] in the case that prevention measures are not sufficient or cannot be implemented. Meteorological forecasting of suitable quality and lead-time should be used for the prediction of the hydrological conditions

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