Rainfall event trends in the Júcar River Water Authority area (1989-2016): From resource to the risk

Abstract

This work approaches the study of rainfall events in Mediterranean environments. The area of study is that of the Júcar River Water Authority. More than 600 episodes have been selected (1989-2016) from the original five-minute rainfall information according to hydrological criteria. Episodes have been described by indicators of accumulated precipitation, intensity, and persistence. Through a cluster analysis, the episodes have been classified into three typologies (limited resources, long-term resources, and risky episodes). The temporal evolution of each event class has been analysed, establishing differences between the inland and coastal episodes. The results show a generalised trend towards increasing risk at the expense of decreased resources - due to less accumulated rainfall and an increase in intensities. Despite an increasing annual frequency of events, the significance of risk events is more important than those of resource events. This behaviour is more pronounced in the inland areas than on the coast. Moreover, a monthly shift in the event type occurrence is observed: events that contribute a great deal of rainfall are moving from October to November, favouring the monthly coincidence of high precipitation episodes and intense episodes. This synergy between copious and intense events is an added risk factor.