Weakening flood, intensifying hydrological drought severity and decreasing drought probability in Northeast China

Study region: Northeast China Study focus: Northeast China is one of the largest agricultural regions in the world and a strategically important granary for China. Information on hydrological extremes is crucially important for water management. Yet, comprehensive studies on hydrological extremes, both extreme flood and drought events, based on hydrological gauge comprehensive and large coverage observations are still lacking in Northeast China. This study investigated observed hydrological extremes with 124 hydrological gauges in the region ranging from the 1950s to present for the first time. New hydrological insights for the region: We find that flood extremes, mean discharge and standardized discharge are decreasing in over 80% of the gauges, and no gauges show significantly increasing flood extremes. The findings suggest that sustainable water management strategies should be employed to meet increasing water demand for long-term development. In addition, we find that flood peak discharge and flood volume are significantly correlated in all the gauges, motivating flood risk studies considering multiple flood variables together. Further, we quantify probability changes of severe and extreme hydrological droughts, and find that the probability of drought events is decreasing in most of the gauges, suggesting that the number of drought events is reducing. Data availability: Discharge data are from the hydrology bureau, and can be found by contacting Songliao River Water Resources Commission, Ministry of Water Resources, the People’s Republic of China (http://www.mwr.gov.cn/english/).