A number of hydrological models developed in the later part of the 20thcentury run the risk of becoming obsolete. One such model, CEQUEAU, was reprogrammed by its main industrial user, Rio Tinto Alcan. CEQUEAU is aconceptual semi-distributed that can simulate/forecastdaily/hourly flow, as well as daily water temperature. The new version of the model maintains the conceptual, hydrological budget and soil reservoir approachof the original one. However, the format structure is less restrictive than the original FORTRAN code. It allowed for new modules to be tested. Input physiographic and water routing data can now be extracted using a GIS and matlab script. Two additional snow melt routines are being implemented (CEMANEIGE and the Utah Energy Balance model). A total of six different potential evapotranspiration algorithms are being tested and compared. In addition, an automatic calibration algorithm based on depth functions and the Tabu Search protocol is being implemented. The water temperature model was also improved. The time step of some meteorological input data was changed from monthly to daily and the model is now able to account for the impacts of dams on the thermal regime.