Hydrological modeling in Modelica

Hydrological modeling is an area where modeling has been used for a very long time. Applications range from forecasts for the hydro power industry, public safety, agriculture and environmental monitoring. Still, to the best of our knowledge, Modelica has been very little used in hydrological modeling so far. In this paper, we aim to show that the Modelica language is well suited for hydrological modeling and also to outline a possible future development of libraries in order to further facilitate hydrological modeling and coupling of hydrological models to other types of models in Modelica. A Modelica implementation of the hydrological HBV model is compared with the original Fortran model. The main advantages of using Modelica as modeling language are more readable and re-usable code and better abstraction. The disadvantage is longer execution times compared to the Fortran model. The HBV model is a quite simple model mathematically. It would be useful to investigate the behaviour of more complex hydrological models as well in order to see whether we can find the same advantages of using Modelica as modeling language in that respect as we have in the case with the HBV model.