Seasonal forecast of cooling water problems in the River Rhine

Cooling water scarcity in the River Rhine due to low flows during summer and high water temperatures may endanger power supply in the Netherlands and Germany. This research addresses the feasibility of early warning for cooling water problems on a seasonal timescale using large-scale oceanic and atmospheric patterns as predictors. The correlation strength, stability as well as probabilistic skill of possible teleconnections were assessed. The strongest teleconnection was found between January North Atlantic Oscillation (NAO) and August water temperatures. The evaluated teleconnections between NAO and El Niño Southern Oscillation (ENSO) and discharge do not increase skill compared to only using information on discharge itself in the winter and spring months. In pseudo-operational context model results were shown to be very sensitive to the choice of predictor selection criteria significance and stability. Though for some responses statistically significant forecasts were found, discussion and research with stakeholders about handling risk levels and probabilistic forecasts would be required to assess the practical significance of the forecasts.