Climate, Irrigation, and Land Cover Change Explain Streamflow Trends in Countries Bordering the Northeast Atlantic

• Published in: Geophysical Research Letters
• Main Authors: Vicente‐Serrano, S. M., Peña‐Gallardo, M., Hannaford, J., Murphy, C., Lorenzo‐Lacruz, J., Dominguez‐Castro, F., López‐Moreno, J. I., Beguería, S., Noguera, I., Harrigan, S., Vidal, J.P.
• Other Authors: CSIC CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS ESP, CEH CENTRE FOR ECOLOGY AND HYDROLOGY WALLINGFORD GBR, MAYNOOTH UNIVERSITY IRE, UNIVERSITY OF THE BALEARIC ISLANDS ESP, ECMWF EUROPEAN CENTRE OF MEDIUM RANGE WEATHER FORECASTS GBR, IRSTEA LYON UR RIVERLY FRA
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: RESSOURCE EN EAU; CHANGEMENT CLIMATIQUE; IRRIGATION; OCCUPATION DU SOL; WATER RESOURCES; PRECIPITATION; ATMOSPHERIC EVAPORATIVE DEMAND; CLIMATE CHANGE; DROUGHT; LAND COVER; RESSOURCES EN EAU; PRÉCIPITATION; DEMANDE EVAPORATIVE DE L'ATMOSPHERE; SECHERESSE; climatic change; land occupation; Northeast Atlantic
• Online Access: https://irsteadoc.irstea.fr/cemoa/PUB00064033

Attribution of trends in streamflow is complex, but essential, in identifying optimal management options for water resources. Disagreement remains on the relative role of climate change and human factors, including water abstractions and land cover change, in driving change in annual streamflow. We construct a very dense network of gauging stations (n = 1,874) from Ireland, the United Kingdom, France, Spain, and Portugal for the period of 1961-2012 to detect and then attribute changes in annual streamflow. Using regression‐based techniques, we show that climate (precipitation and atmospheric evaporative demand) explains many of the observed trends in northwest Europe, while for southwest Europe human disturbances better explain both temporal and spatial trends. For the latter, large increases in irrigated areas, agricultural intensification, and natural revegetation of marginal lands are inferred to be the dominant drivers of decreases in streamflow.