Hydrol. Earth Syst. Sci. 22, 5935–5946 (2018)

Changes to the hydrological cycle are expected to affect water security. Water storage consists of blue water (surface water) and green water (that stored in soil), but how water will be distributed between them in the future is unclear. A shift to more extreme precipitation could influence storage, and Joris Eekhout of the Soil and Water Conservation Research Group, Murcia, Spain, and colleagues applied a hydrological model, coupled with a soil erosion model, to study these effects. They investigate the Segura River catchment, southeast Spain, for the periods 2031–2050 and 2081–2100 under RCP 4.5 and 8.5.

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age fotostock/Alamy Stock Photo.

The results show redistribution in the future with less green water, which causes greater plant water stress and necessitates more irrigated agriculture. The shift to blue water storage, with greater runoff into streams and reservoirs, will also increase soil erosion and overall reduce water security. The authors attribute the change to increased extreme precipitation and a decreased frequency of precipitation. To ensure water security, adaptation should consider increasing soil and reservoir storage capacity through sustainable land management.