From Flood to Drip Irrigation Under Climate Change: Impacts on Evapotranspiration and Groundwater Recharge in the Mediterranean Region of Valencia (Spain)

[EN] Agricultural irrigation is the major water consumer in the Mediterranean region. In response to the growing pressure on freshwater resources, more efficient irrigation technologies have been widely promoted. In this study, we assess the impact of the ongoing transition from flood to drip irrigation on future hydroclimatic regimes under various climate change scenarios, with a particular focus on actual evapotranspiration and groundwater recharge in the Mediterranean region of Valencia, Spain. Hydroclimatic predictions for the near-term future (2020-2049) and the mid-term future (2045-2074) were made under two emission scenarios (RCP 4.5 and RCP 8.5) using a hydrological model that was forced with data from five GCM-RCM combinations and field-based irrigation volume and frequency observations. Our findings suggest that climate change could lead to statistically significant changes in the regional hydroclimatic regime despite projection uncertainties. Major changes include a statistically significant decrease in mean groundwater recharge of up to -6.6% under flood irrigation and -9.3% under drip irrigation and contrasting changes in mean actual evapotranspiration for flood and drip irrigation in the order of +1% and -2.1%, respectively. Since sustainably available water resources in the Valencia region are entirely allocated, the expected changes and associated uncertainties create a challenging context for future water management. Our simulations further indicate that, rather than climate change, the choice of irrigation technique may have a greater impact on actual evapotranspiration and groundwater recharge. Our findings therefore highlight the importance of considering both climate change and irrigation technique when assessing future water resources in irrigated Mediterranean agriculture.The authors thank the Coop Research Program on "Sustainability in Food Value Chains" of the ETH Zurich World Food System Center and the ETH Zurich Foundation for supporting this project. The Coop Research Program is supported by the Coop Sustainability Fund. The authors further thank the Spanish Ministry of Science and Innovation through the research project TE-TISCHANGE (RTI2018-093717-B-100) for financial support. This work was also supported by the ADAPTAMED research project funded by the Spanish Ministry of Science and Innovation (RTI2018-101483-B-I00) with European FEDER funds.Pool, S.; Francés, F.; Garcia-Prats, A.; Pulido-Velazquez, M.; Sanchis Ibor, C.; Schirmer, M.; Yang, H.... (2021). From Flood to Drip Irrigation Under Climate Change: Impacts on Evapotranspiration and Groundwater Recharge in the Mediterranean Region of Valencia (Spain). Earth's Future. 9(5):1-20. https://doi.org/10.1029/2020EF001859S1209

Air quality modelling in Catalonia from a combination of solar radiation, surface reflectance and elevation

Air quality in developed areas is being increasingly compromised by the effect of urbanization, which is favouring the presence of atmospheric pollutants derived from human-induced activities. Land cover change is one of the consequences most closely associated with urbanization, leading to a growing presence of dark built-up surfaces. The target of this investigation was to model the Catalonian Air Quality Index (CAQI) from the combined effect of the surface reflectance capacity of urban surfaces with solar radiation and elevation. Geoprocessing tools were used to produce the information required to characterise these variables in the buffer areas surrounding 75 different air quality monitoring stations located across the region. Cluster analysis and Multiple Linear Regression (MLR) were applied to group these stations according to their similarity and replicate the annual mean values of CAQI recorded in Catalonia in 2011, respectively. Finally, discriminant analysis enabled assigning ungauged areas to the cluster and MLR model that best fitted their solar radiation, surface reflectance and elevation features. The implementation of this approach resulted in highly accurate predictions of CAQI, providing a mechanism of identification of areas having a number of days with poor air quality during the year. Since these areas were related to the presence of land cover types with high sunlight absorption, the proposed methodology was suggested to support the adoption of measures aimed at controlling urban air pollution based on replacing built-up surfaces by green infrastructure.This paper was possible thanks to the research project SUPRIS-SUReS (Ref. BIA2015-65240-C2-1-R MINECO/FEDER, UE), financed by the Spanish Ministry of Economy and Competitiveness with funds from the State General Budget (PGE) and the European Regional Development Fund (ERDF). The authors also wish to express their gratitude to all the entities that provided the data necessary to develop this study: the Department of Statistics and the Directorate of Environmental Monitoring of the Barcelona City Council, the Cartographic and Geological Institute of the Government of Catalonia and the National Centre of Geographic Information (CNIG) of the Spanish Ministry of Public Works and Transport

Guide economique des systemes d'information geographique

Available at INIST (FR), Document Supply Service, under shelf-number : RP 12266 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Systemes d'information geographique et gestion durable de l'eau

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : RL 601 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc