Loading...
Publication
Indicadores de desempenho em resposta a seca hidrológica nos aquíferos do Algarve
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 607.74 KB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
As águas subterrâneas desempenham um papel vital na sustentação dos ecossistemas e na segurança alimentar durante as secas. As alterações climáticas, nomeadamente o aumento das temperaturas e a redução da precipitação, estão a agravar as situações de escassez de água em zonas semiáridas e a colocar em risco a sustentabilidade dos aquíferos costeiros. Apesar da necessidade urgente de monitorizar e gerir os recursos hídricos, a natureza heterogénea dos aquíferos torna difícil avaliar e prever o estado quantitativo das águas subterrâneas. O Índice Padronizado de Níveis de Água Subterrânea ou Standardized Groundwater Index (SGI) emergiu como um índice comparável com outros índices meteorológicos de seca (Bloomfield and Marchant, 2013) e oferece uma alternativa ao limiar do percentil 20 da série histórica do nível piezométrico, tradicionalmente usado pela Agência Portuguesa do Ambiente para classificar o estado quantitativo das massas de água subterrânea. Este estudo foca-se no Algarve, uma região mediterrânica semiárida com aquíferos costeiros fortemente impactados pela seca. Ao comparar diferentes índices de seca, como o SGI, o Índice Padronizado de Precipitação e Evapotranspiração (SPEI) e indicadores de desempenho, a investigação procura fornecer melhores ferramentas para a gestão das águas subterrâneas. O objetivo é melhorar a capacidade de antecipar secas e implementar estratégias de mitigação, contribuindo para uma gestão mais sustentável dos recursos hídricos.
Aquifers in semi-arid coastal regions such as the Algarve are severely affected by droughts. Excessive groundwater abstraction exacerbates the situation, leading to the degradation of water quality and the risk of saline intrusion. Thoroughly monitoring using various indicators is crucial to predicting and mitigating the consequences of drought. This study proposes a methodology that involves calculating performance indicators based on the Standardized Groundwater Index (SGI) and the Standardized Precipitation Evapotranspiration Index (SPEI). Atmospheric reanalysis data and in situ groundwater level observations are used to determine the aquifers' memory and to find optimal accumulation times for the SPEI at each well. The inverse of the memory calculated from the SGI's autocorrelation provides the best estimate of each well's recovery capacity under drought conditions, offering a reliable indication of resilience and sustainability. The SPEI calculated for an accumulation time of 12 months (SPEI-12) best captures the average regional variability of groundwater levels. However, aquifer memories and optimal SPEI accumulation times vary greatly spatially, ranging from SPEI-5 to SPEI-48. Wells with shorter memories (< 6 months) demonstrate greater sustainability, while those with longer memories (> 16 months), inland or along the coast, exhibit lower resilience and sustainability. This work identifies the wells with the least resilience that require intensified monitoring to adapt water management strategies.
Aquifers in semi-arid coastal regions such as the Algarve are severely affected by droughts. Excessive groundwater abstraction exacerbates the situation, leading to the degradation of water quality and the risk of saline intrusion. Thoroughly monitoring using various indicators is crucial to predicting and mitigating the consequences of drought. This study proposes a methodology that involves calculating performance indicators based on the Standardized Groundwater Index (SGI) and the Standardized Precipitation Evapotranspiration Index (SPEI). Atmospheric reanalysis data and in situ groundwater level observations are used to determine the aquifers' memory and to find optimal accumulation times for the SPEI at each well. The inverse of the memory calculated from the SGI's autocorrelation provides the best estimate of each well's recovery capacity under drought conditions, offering a reliable indication of resilience and sustainability. The SPEI calculated for an accumulation time of 12 months (SPEI-12) best captures the average regional variability of groundwater levels. However, aquifer memories and optimal SPEI accumulation times vary greatly spatially, ranging from SPEI-5 to SPEI-48. Wells with shorter memories (< 6 months) demonstrate greater sustainability, while those with longer memories (> 16 months), inland or along the coast, exhibit lower resilience and sustainability. This work identifies the wells with the least resilience that require intensified monitoring to adapt water management strategies.
Description
Keywords
Drought Aquifer Performance SPEI SGI Sustainability Water Resources Algarve. Seca Aquífero Desempenho Recursos Hídricos Algarve
Citation
Publisher
Universidade de Évora