Groundwater and baseflow drought responses to synthetic recharge stress tests

Abstract. Groundwater is the main source of freshwater and maintains streamflow during drought. Potential future groundwater baseflow drought hazards depend on systems' sensitivity to altered recharge conditions. We performed model experiments using three different generic stress tests estimate changes in recharge. The stem from a stakeholder co-design process that specifically followed idea altering known events past, i.e. asking whether could have made particular event worse. Across Germany, responses are highly heterogeneous, with heads north more sensitive long-term Central German Uplands short-term variations. Baseflow droughts generally intra-annual dynamics, smaller compared heads. recovery time mainly driven by hydrogeological conditions, slow (fast) porous (fractured rock) aquifers. In general, seasonal shift (i.e. less summer winter recharge) will lesser effects severity. A lengthening dry spells might cause much stronger responses, especially regions response precipitation. Water management may need consider spatially sensitivities system potential for severe large aquifers following prolonged meteorological droughts, particularly context climate change projections indicating seasonality events.