Drought propagation through the hydrological cycle

Time series of simulated recharge, groundwater heads and streamflow were obtained for temperate humid and semiarid climate regions and for quickly and slowly-responding catchments. These were analysed to investigate the propagation of drought through the subsurface, i.e. the change in characteristics (onset, duration and severity) from a meteorological drought to a hydrological drought. In two selected contrasting climate regions (Spain and The Netherlands) the propagation of recharge droughts generally leads to smaller hydrological droughts, except for severe recharge droughts, which might generate very severe hydrological droughts. In quickly-responding catchments more minor droughts will occur, whereas the probability of a very severe drought is higher in slowly-responding catchments. It is anticipated that quantitative knowledge on drought propagation will advance if recharge droughts derived from real instead of synthetic recharge can be better defined, i.e. by use of recharge anomalies.