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Authors
Abstract(s)
As alterações climáticas terão impactos significativos na agricultura, em particular nas regiões mediterrâneas. Com a subida da temperatura e as mudanças na quantidade e distribuição da precipitação, prevê-se um aumento das necessidades hídricas das culturas e, consequentemente, uma maior dependência do regadio. Torna-se, por isso, importante conhecer de que modo estes fatores podem influenciar o dimensionamento de redes de rega coletivas, de modo a averiguar a necessidade de adaptações à metodologia utilizada atualmente e a fim de garantir que as infraestruturas estejam aptas a satisfazer as necessidades durante o período de vida útil do projeto.
O presente estudo teve como objetivo geral incluir as alterações climáticas no dimensionamento da rede de rega em pressão, com fornecimento a pedido, do Aproveitamento Hidroagrícola do Crato, localizado no distrito de Portalegre (Portugal). Para tal, foram realizadas três versões de dimensionamento: i) com base em dados climáticos do período 1991-2020; ii) com base em projeções do cenário climático RCP4.5 (2041-2070) e iii) com base em projeções do cenário climático RCP8.5 (2041-2070). Pretendeu-se ainda fazer uma comparação qualitativa do desempenho de dois softwares de dimensionamento de redes de rega, o SIGOPRAM e o programa usualmente utilizado na empresa Campo d’Água (CA).
Verificou-se que o caudal de dimensionamento da rede aumentou apenas 2.9 % (RCP8.5), em relação ao período 1991-2020, podendo concluir-se que a vida útil do projeto (cerca de 30 anos) é demasiado curta para que se verifique, nas projeções 2041-2070, uma alteração significativa das necessidades de rega das culturas em período de ponta. Os resultados parecem indicar que, para as condições do presente estudo, tais como o clima, o padrão cultural, as projeções climáticas utilizadas e o período considerado, a inclusão do impacto das alterações climáticas não introduz alterações no dimensionamento da rede secundária. Verificou-se ainda, que os softwares SIGOPRAM e CA calcularam caudais de dimensionamento com apenas 0.7 % de diferença, destacando-se a maior agilização do dimensionamento obtida com o primeiro e a maior flexibilidade do segundo.
Climate change will significantly impact agriculture, particularly in Mediterranean regions. With a rise in temperature and changes in the quantity and distribution of precipitation, an increase in crop water requirements is expected, leading to a greater reliance on irrigation. Therefore, it becomes important to understand how these factors might influence water distribution network design, so that designers may assess the need to adapt the design methodology, to not compromise the infrastructure’s ability to meet demands during the project’s lifespan. The present study aimed to include climate change in the design of the on-demand pressurized irrigation water distribution network of the Crato Irrigation Scheme, located in Portalegre (Portugal). To this end, three design assessments were conducted: i) based on climate data from the 1991-2020 period; ii) based on projections from the RCP4.5 climate scenario (2041-2070); and iii) based on projections from the RCP8.5 climate scenarios (2041-2070). Additionally, the study sought to make a qualitative comparison of the performance of two irrigation network design software programs, SIGOPRAM and the software currently used by Campo d’Água (CA). It was observed that the design flow of the network increased by only 2.9% (RCP8.5), in relation to the 1991-2020 period, leading to the conclusion that the project's lifespan (approximately 30 years) is too short to significantly alter crop irrigation requirements during peak periods when relying on projections for 2041-2070. The results appear to indicate that, for the conditions of the present study, such as the climate, the cropping pattern, the climate projections used and the period considered, the inclusion of the impact of climate change does not introduce changes in the sizing of the secondary network. It was also noted that the SIGOPRAM and CA software programs calculated design flows with only a 0.7% difference, with the former standing out for its greater efficiency in sizing and the latter for its increased flexibility.
Climate change will significantly impact agriculture, particularly in Mediterranean regions. With a rise in temperature and changes in the quantity and distribution of precipitation, an increase in crop water requirements is expected, leading to a greater reliance on irrigation. Therefore, it becomes important to understand how these factors might influence water distribution network design, so that designers may assess the need to adapt the design methodology, to not compromise the infrastructure’s ability to meet demands during the project’s lifespan. The present study aimed to include climate change in the design of the on-demand pressurized irrigation water distribution network of the Crato Irrigation Scheme, located in Portalegre (Portugal). To this end, three design assessments were conducted: i) based on climate data from the 1991-2020 period; ii) based on projections from the RCP4.5 climate scenario (2041-2070); and iii) based on projections from the RCP8.5 climate scenarios (2041-2070). Additionally, the study sought to make a qualitative comparison of the performance of two irrigation network design software programs, SIGOPRAM and the software currently used by Campo d’Água (CA). It was observed that the design flow of the network increased by only 2.9% (RCP8.5), in relation to the 1991-2020 period, leading to the conclusion that the project's lifespan (approximately 30 years) is too short to significantly alter crop irrigation requirements during peak periods when relying on projections for 2041-2070. The results appear to indicate that, for the conditions of the present study, such as the climate, the cropping pattern, the climate projections used and the period considered, the inclusion of the impact of climate change does not introduce changes in the sizing of the secondary network. It was also noted that the SIGOPRAM and CA software programs calculated design flows with only a 0.7% difference, with the former standing out for its greater efficiency in sizing and the latter for its increased flexibility.
Description
Mestrado em Engenharia Agronómica. Área de especialização: Engenharia Rural. Universidade de Lisboa, Instituto Superior de Agronomia
Keywords
caudal de dimensionamento fórmula de Clément cenários RCP ISAREG SIGOPRAM design flow Clément formula RCP scenarios
Pedagogical Context
Citation
Cabral, P.M.L. Dimensionamento da rede de rega coletiva do aproveitamento hidroagrícola do Crato em cenário de alterações climáticas. Lisboa: ISA-Universidade de Lisboa, 2023. Dissertação de Mestrado
Publisher
Instituto Superior de Agronomia, Universidade de Lisboa