Low flow sensitivity in central and southwestern Europe to water withdrawals under 2K global warming

Abstract

A sufficient freshwater supply is vital for humans, ecosystems, and economies, but anticipated climate and socio-economic change are expected to substantially alter water availability. Across Europe, about 2/3 of the abstracted freshwater comes from rivers and streams. Various hydrological studies address the resulting need for projections on changes in river discharge. However, those assessments rarely account for the impact of various water withdrawal scenarios during low flow periods. We present here a novel, high-resolution hydrological modeling experiment using pseudo-global warming climate data to investigate the effects of changing water withdrawals under 2K global warming. We find substantial sensitivities in projected low flows to varying water withdrawal assumptions, especially across Western and Central Europe. Our results highlight the importance of accounting for future water withdrawals in low flow projections, showing that climate-focused impact assessments in near-natural catchments provide only one piece of the anticipated response and do not necessarily reflect changes in heavily managed river basins.