Loading...
Publication
Avaliação do impacto das alterações climáticas na bacia de drenagem do Lavradio
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 3.92 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
As inundações em meio urbano estão na origem de pesados encargos para a
sociedade e economia, como revelam dados divulgados pela comissão europeia.
Fenómenos como a impermeabilização de terrenos devido à sua urbanização, que para
além do acréscimo de volume de escoamento aumentam também a velocidade do
escoamento superficial, provocam reduções nos tempos de concentração e de resposta das
bacias hidrográficas originando inundações. Atualmente é ainda necessário considerar
fatores derivados das alterações climáticas visto que, com o aumento da temperatura média
no planeta e consequente derretimento das calotas polares, prevê-se a subida do nível
médio das águas do mar colocando em risco territórios costeiros a cotas reduzidas.
Também a alteração e disrupção dos regimes de precipitação, nos quais se constata uma
diminuição do número de fenómenos e um aumento da sua intensidade, passará a ser cada
vez mais comum, o que agrava a problemática das inundações.
Neste contexto, o presente trabalho consiste na avaliação do impacto das alterações
climáticas no sistema de drenagem urbana do Lavradio, no município do Barreiro. Este
sistema inclui uma bacia de retenção e a jusante desta, uma vala que descarrega no
estuário do rio Tejo. A sua localização pode tornar o sistema suscetível de sofrer eventos
extremos, com efeitos gravosos para a população, quando existe simultaneidade da subida
da maré com picos de pluviosidade mais intensos. Assim, caracterizou-se esse sistema,
com o apoio e disponibilização de dados por parte da Câmara Municipal do Barreiro, e
estudou-se uma parte desse sistema constituída por três sub-bacias hidrográficas que
descarregam, através de coletores e de uma vala a céu aberta, numa bacia de retenção.
Considerou-se, para efeitos de avaliação do impacto das alterações climáticas, a situação
atual e também diferentes cenários de alterações climáticas, recorrendo, para tal, à recolha
de dados associados à pluviosidade e procedendo-se à modelação, através do software
SWMM, de forma a realizar um diagnóstico e a desenvolver uma solução de melhoria a
apresentar à Entidade Gestora.
Floods in urban areas can cause of heavy losses, both for civil society and for the economy, as shown by data released by the European Commission. Phenomena such as the waterproofing of ground due to urbanization, which, in addition to increasing the volume of runoff, also increase the speed of surface runoff, causing reductions in the concentration and response times of the hydrographic basins, which in turn causes flooding. Currently, it is still necessary to consider factors derived from climate change since, with the increase in the average temperature on the planet surface, and the consequent melting of the polar ice caps, an increase in the average sea level is expected to put coastal territories at low levels at risk. Also the change and disruption of precipitation regimes, in which there is a reduction in the number of phenomena and an increase in their intensity, will become increasingly common, which aggravates the problem of flooding. The present dissertation arises in the context previously described and consists in evaluating the impact of climate change on the Lavradio urban drainage system, in the municipality of Barreiro. This system includes a retention pond and, downstream is an open drain that discharges into the Tagus River estuary. Its location can make the system susceptible to suffering extreme events, with serious effects on the population, when there is a simultaneous rise in the tide with more intense rainfall peaks. Thus, the referred system was characterized, with the support of the Municipality of Barreiro technicians. In this work a part of the system consisting of three hydrographic sub-basins that discharge, through collectors and an open drain, in a retention pond was modelled and studied. The current situation and different climate change scenarios were considered in order to assess the impact of climate change. The collection of data associated with the terrain, the basin, and the rainfall regimes, were used for this purpose. With the aid of SWMM software it was possible to carry out a diagnosis to be presented to the system’s Water Utility.
Floods in urban areas can cause of heavy losses, both for civil society and for the economy, as shown by data released by the European Commission. Phenomena such as the waterproofing of ground due to urbanization, which, in addition to increasing the volume of runoff, also increase the speed of surface runoff, causing reductions in the concentration and response times of the hydrographic basins, which in turn causes flooding. Currently, it is still necessary to consider factors derived from climate change since, with the increase in the average temperature on the planet surface, and the consequent melting of the polar ice caps, an increase in the average sea level is expected to put coastal territories at low levels at risk. Also the change and disruption of precipitation regimes, in which there is a reduction in the number of phenomena and an increase in their intensity, will become increasingly common, which aggravates the problem of flooding. The present dissertation arises in the context previously described and consists in evaluating the impact of climate change on the Lavradio urban drainage system, in the municipality of Barreiro. This system includes a retention pond and, downstream is an open drain that discharges into the Tagus River estuary. Its location can make the system susceptible to suffering extreme events, with serious effects on the population, when there is a simultaneous rise in the tide with more intense rainfall peaks. Thus, the referred system was characterized, with the support of the Municipality of Barreiro technicians. In this work a part of the system consisting of three hydrographic sub-basins that discharge, through collectors and an open drain, in a retention pond was modelled and studied. The current situation and different climate change scenarios were considered in order to assess the impact of climate change. The collection of data associated with the terrain, the basin, and the rainfall regimes, were used for this purpose. With the aid of SWMM software it was possible to carry out a diagnosis to be presented to the system’s Water Utility.
Description
Keywords
Alterações climáticas Bacia de retenção Drenagem pluvial Inundações urbanas Climate change Rainwater drainage system Retention basin Urban flooding