Abstract
Machico, a parish located in Madeira, Portugal, is prone to recurring floods during periods of heavy rainfall, which can cause significant damage to property, infrastructure, and even put the lives of people and animals at risk. The increasing urbanization has worsened this problem since urban growth often occurs in risk-prone areas, such as steep slopes or floodplains. Additionally, the development of drainage and flow systems often cannot keep up with the pace of urban expansion, leading to greater vulnerability to flooding. Therefore, it is essential to conduct studies to better understand how urbanization contributes to flooding to develop more effective risk management strategies. This involves identifying risk-prone areas, establishing prevention and damage mitigation measures, and implementing early warning systems to protect the population in the event of extreme weather conditions.
TopIntroduction
Floods are one of the phenomena that become more and more frequent and destructive due to the disorderly growth of cities and the lack of adequate urban planning (Freitas & Andrade, 2007). Thus, it is clear that floods are the most common type of natural disaster in Europe, taking into account the international database on disasters, representing 43% of all disasters that occurred during the period between 1998 and 2002 (EEA, 2005). The potential effects of climate change and changing environmental conditions on flooding events threatens to exacerbate urban flood risk worldwide (Miller & Hutchins, 2017; Skougaard Kaspersen et al., 2017), requiring adaptation and further lot-scale mitigation to protect property from water damage (Leandro et al., 2020). Floods can be defined as extreme hydrological phenomena of variable frequency. These events could be natural or human-induced, consisting of the overflow of a watercourse (Chow, 1956) e (Guedes, 2014). With the increase of this problem at a global level and, mainly in tropical regions, it became necessary to develop measures and devices to mitigate the impacts of floods (Lousada & Castanho, 2021; Lousada et al., 2021).
Floods, depending on the size of the flow in the surrounding area, affect settlements and agriculture by damaging their areas, lower and upper structures, facilities, and living things, and they interrupt human life and socio-economic activities. Issues concerning urban flooding have been identified in regions across the globe (Zhu & Chen, 2017; Mobini et al., 2020; Pagliacci et al., 2020). Sociological effects on humans from floods, psychological disorders, and the like, are also seriously affected (Lousada et al., 2022).
Considering that the elevation of the Machico stream occasionally causes flooding in the Machico parish and that these events affect the lives of citizens, it was decided to study the occurrence of this phenomenon. The characterization of the runoff factors in the Machico parish and the surrounding region (from the Machico stream mouth to the mountains at 1000 m altitude), together with the historical analysis of floods, the study of the urbanization process and the constraints on surface runoff (Ramos, 2009; DGRAH, 1984; Quintal, 1999; Barreto, 2013; Hipólito & Vaz, 2011) and the calculation of flood risk allow for a better understanding of the conditions under which the phenomenon occurs and how it manifests itself. Based on this information, the objective of this study is to project the future of floods (Deltares, 2010; SRARN, 2016) in the city of Machico, creating scenarios that allow for the definition of mitigation measures to reduce the harmful effects that these floods can cause. This can include citizen participation in hazard mitigation policy (Oulahen & Doberstein, 2012) which engages the public in the area of flood risk and vulnerability and the adoption of technologies to reduce this risk. This aids in developing an awareness for homeowners of the infrastructure present in the home and the requirements for homeowner maintenance (Sandink, 2011; Owusu et al., 2015).
The methodology of this study involves the characterization of the urbanization process, through the analysis of the variation in the number of buildings and residents in the Machico parish, as well as the development of maps of impermeable areas at different temporal moments, allowing an evaluation of how this process has occurred. It is observed that the urbanization process in the Machico parish is related to the number of buildings and residents in the region, as well as the evolution of impermeable areas over time.
Key Terms in this Chapter
Floods: Floods refer to the overflow of water beyond its normal or natural confines, covering usually dry land areas.
Heritage: Heritage refers to cultural or natural assets that are considered to have significant value and importance for present and future generations. These assets can include sites, monuments, buildings, landscapes, or other tangible or intangible elements that represent a society's past and contribute to its identity.
Urbanization: Urbanization is the process by which an increasing proportion of a population lives in urban areas, characterized by high population density, infrastructure, and economic activity. It involves the growth and expansion of cities and urban centers, often accompanied by changes in land use, social structure, and cultural norms.
Floodings: Flooding is the act or process of water overflowing from its natural channels or boundaries, causing water to spread over usually dry land areas, often causing damage or inconvenience.
Machico: Portuguese municipality on the island of Madeira, Autonomous Region of Madeira, where Tristão Vaz Teixeira and João Gonçalves Zarco landed in 1419 when they discovered the island of Madeira.
Madeira: Madeira - Madeira is a Portuguese archipelago located in the Atlantic Ocean, consisting of two inhabited islands, Madeira and Porto Santo.