The frequent floods of cities, such as those that occurred in June 2010 in the municipalities of Pernambuco and Alagoas, causing the death of more than 40 people, has drawn society's attention to this phenomenon. However, it is necessary to clarify that urban floods can occur due to several factors, the main ones being the inefficiency of the drainage system and the construction of urban centers on land that is naturally affected by floods.
This process promotes the destruction of infrastructure in the affected cities, agricultural losses, the spread of diseases, causing homeless people, injuries, deaths, etc. These floods can be triggered in riverside areas, as a result of poor urban planning, in addition to localized floods.
Floods in riparian areas are those that occur periodically in floodplains and the determining factor is the geomorphological. Therefore, in this case, the actions of urban projects (soil compaction, deforestation, paving, etc.) are not the main responsible for the floods, as these areas are naturally subject to flooding, as they are very close to the courses of Water.
Floods due to urbanization are those caused by deforestation, intensifying surface runoff, waterproofing the urban site, inadequate construction of dikes, alteration of the natural courses of rivers, ineffective rainwater catchment projects (rain). All these aspects favor the occurrence of floods in periods of heavy rainfall.
Localized floods are caused by human interventions in drainage, with strangulation of riverbeds in bridges, culverts and landfills. Silting aggravates this situation, as it reduces the sections of the channels and can also cause localized flooding.
As measures to prevent the occurrence of floods are urban planning, not building cities in riverside areas, development of effective engineering projects for the capture of rainwater (dikes, culverts, etc.), land occupation policies, environmental education, among others.
By Wagner de Cerqueira and Francisco
Graduated in Geography
Source: Brazil School - https://brasilescola.uol.com.br/geografia/inundacoes-urbanas.htm
