Urban Stormwater Management, a Tool for Adapting to Climate Change: From Risk to Resource

María Hernández-Hernández,Jorge Olcina,Álvaro-Francisco Morote

doi:10.3390/w12092616

Abstract

The effects of climate change on rainfall in the Mediterranean region are manifested in an overall decreasing trend, and greater irregularity in annual volumes and the city of Alicante is no exception. In addition, there has also been a spread of the urbanised area, which has led to an increase in the flood risk in urban areas (due to a greater runoff and the occupation of flood hazard areas) and drought events due to an increase in the water demand. In light of these new scenarios, the Mediterranean cities should design adaptation systems based on rainwater harvesting within the framework of a circular economy. This study analyses the integration of rainwater in flood and water demand management in the city of Alicante (Southern Spain). In recent years, this city has developed infrastructures in order to use these resources. To do this, different databases have been analysed (rainfall and volume of water collected in the green infrastructure systems). The results reveal that stormwater has become highly important in urban water management in Alicante as the city is now using a resource that previously went to waste and created problems (flooding and pollution). By way of conclusion, it is worth mentioning that the incorporation of rainwater for urban use in Alicante has reduced the pressure on traditional resources in satisfying water demand and has also acted as a measure for adapting to climate change.

Highlights

The use of rainwater is a traditional technique based on collecting rainfall and was historically used in the Mediterranean and other semi-arid territories [1]
The objectives of this study are: (1) to confirm the change of rainfall stated by studies as a result of climate change given its impact on the availability of water resources; (2) to examine the incorporation of rainwater in the management of water demand in the city of Alicante (Southern Spain), taking into account its purpose and the volumes stored; and (3) to propose future action for harvesting and using rainwater in a scenario of adaptation to climate change
Data have been drawn from various sources: (1) daily rainfall data from the Ciudad Jardín observatory (Alicante) (1980–2019) to establish the increase in the intensity of the rainfall and, indirectly, the greater torrential nature of rainfall; (2) data on the volume of water stored in the Green Infrastructure Systems (NBS) existing in the city of Alicante (2011–2019); and (3)

Summary

Introduction

The use of rainwater is a traditional technique based on collecting rainfall and was historically used in the Mediterranean and other semi-arid territories [1]. When the environment did not provide a sufficient level of these resources, attempting to compensate certain resources with others was the maxim guiding the anthropogenic activities in these semi-arid territories These actions can be summarised in a double aptitude: (1) searching for techniques for exploiting rainfall, usually concentrated in a few seasonal episodes; and (2) controlling its erosive capacity and adopting the measures necessary to reduce the runoff coefficients generated in the different riverbeds. In this way, with these techniques, the loss of superficial edaphic horizons was reduced, and an extra source of water was obtained [2]. Moltó and Hernández [4] note in this respect that: (1) the aquifers were recharged, as large areas of land were laminated; (2) erosion was reduced, and the retention of sediments was facilitated as the whole of the ploughed space was

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Conclusion