A while ago, I stumbled upon an interesting paper* where the authors presented a conceptual HBV hydrologic model. This model, which is basically a modification of the original HBV model developed by the Swedish Meteorological and Hydrological Institute (SMHI), takes as input the daily precipitation and temperature and turns this information in simulated streamflow. The processes that get involved in the modelling are: 1) snow melt and snow accumulation, 2) effective precipitation and soil moisture, 3) evapotranspiration and 4) surface response.
I typed down the entire thing in R and ran a simulation (without a calibration of the different parameters), which resulted to the following hydrograph:
Of course, in order to obtain a satisfactory match between observed and simulated streamflow, a calibration criterion must be used such as the Nash-Sutcliffe efficiency or the Pearson correlation coefficient.
The R program can be found here: https://www.dropbox.com/s/rkjo2ntocuirdx2/HBV.R?dl=0
The input data which I used for this example can be downloaded here: https://www.dropbox.com/s/zki5447b9a9rxlz/HBV_data.zip?dl=0
*Aghakouchak, Amir & Habib, Emad. (2010). Application of a Conceptual Hydrologic Model in Teaching Hydrologic Processes. International Journal of Engineering Education. 26. 963-973.