Sensitivity analysis on the continued validity of the Salzach/Inn thermal load plan under changed climate and discharge conditions

Water temperature in rivers is a key factor for the ecological status of aquatic ecosystems and faces growing pressures from climate change, but also from thermal discharges. Existing thermal load models, developed over a decade ago under the climatic and hydrological conditions of that time, raise the question of whether their core assumptions still hold, particularly with regard to shifting seasonal temperature and discharge patterns. Using the Salzach/Inn as a case study, the SENSI-SAI project examines how discharge and water temperature conditions have changed since the original modeling, and builds on this to develop a sensitivity analysis for critical combinations of low discharge and high water temperature. The existing thermal sensitivity between air and water temperature is reassessed using updated time series and scaled to current climate scenarios. In addition, the relevance of glacier retreat for the seasonal discharge dynamics of alpine catchments is contextualized through a literature review. The goal is a robust risk assessment of whether and under what conditions ecological temperature thresholds may be reached or exceeded in the future, along with a well-founded recommendation for action for the client.