Drought and Ecological Flows in the Lower Guadiana River Basin (Southwest Iberian Peninsula)

Abstract

Drought temporal characterization is a fundamental instrument in water resource management and planning of basins with dry-summer Mediterranean climate and with a significant seasonal and interannual variability of precipitation regime. This is the case for the Lower Guadiana Basin, where the river is the border between Spain and Portugal (Algarve-Baixo Alentejo-Andalucía Euroregion). For this transboundary basin, a description and evaluation of hydrological drought events was made using the Standardized Precipitation Index (SPI) with monthly precipitation time series of Spanish and Portuguese climatic stations in the study area. The results showed the occurrence of global cycles of about 25–30 years with predominance of moderate and severe drought events. It was observed that the current requirements of ecological flows in strategic water bodies were not satisfied in some months of October to April of years characterized by severe drought events occurring in the period from 1946 to 2015. Therefore, the characterization of the ecological status of the temporary streams that were predominant in this basin should be a priority in the next hydrologic plans in order to identify the relationships between actual flow regimes and habitat attributes, thereby improving environmental flows assessments, which will enable integrated water resource management.

The Blue Water Footprint of the Spanish Wine Industry: 1935–2015

“…The Guadiana River Basin located in south-west Spain with a dry Mediterranean climate, is another basin where water scarcity represents a challenge for water management. Similarly to the Júcar Basin, since the 1980s the huge development of irrigation increased water demands that represent more than the 75 percent of the total water use [70]. Irrigation water problems are recurrent in this basin, especially in the two main irrigation areas: downstream, in the region of Extremadura, where irrigation relies on surface resources; and upstream, in the region of Castilla-La Mancha where irrigation relies on groundwater resources [71].…”

Tendências de mudança na precipitação e na susceptibilidade à seca avaliada pelo Índice de Precipitação Normalizada (SPI) no nordeste de Portugal

“…do Mar e da Atmosfera) uses PDSI -Palmer Drought Severity Index, developed by Palmer in 1965, which is based on precipitation and temperature data, although IPMA is also applying SPI in internal research projects, following WMO recommendations. Some studies using SPI and PDSI have been conducted in Southern Portugal, as in the Alentejo (Paulo and Pereira, 2006), Algarve and Baixo Alentejo regions (Pulido-Calvo et al, 2020).…”

Assessing the Effects of Environmental Flows on Water Quality for Urban Supply

“…This preservation is fundamental for their continued existence, making a substantial contribution to biodiversity conservation [17,18]. Secondly, they fulfil a pivotal function in maintaining water quality by effectively diluting pollutants and preventing the accumulation of contaminants within aquatic ecosystems [19]. Additionally, e-flows safeguard the ecological equilibrium in rivers, guaranteeing their enduring sustainability [20,21].…”