Evaluation of J2000g model in simulation of snowmelt in Latyan watershed

In mountainous watersheds, snow melt can have a significant impact on the water balance and at certain times of the year it could have the most important contribution to runoff. In many parts of the world snow acts as a natural reservoir that can play an important role for water supply. Specifically, high-altitude basins in semi-arid regions with a significant snow component can have a large capability to balance and distribute scarce water resources. In this study the spatially distributed process-oriented hydrological model J2000g was used for the 431 km² large Latyan catchment in Iran. The target was to derive spatially distributed estimates of the quantity and timing of hydrological balance terms and state variables like rainfall, runoff, snow water equivalent (SWE) and snow melt. The model uses the distribution concept of Hydrological Response Units (HRU) to take the spatial variability in the basin into account. The comparison of the separate SWE models resulted in values between 0.28-0.68 for NSE and values between 0.53-0.83 for R². For the catchment models the comparison of the simulated runoff with measured data showed NSE values between 0.78 and 0.82. By these values it can be stated that the hydrological dynamics and the snow processes of the sub-basins within the Latyan catchment could be simulated sufficiently well with J2000g. It can be summarized that the single modules and in particular the snow components of J2000g along with the HRU distribution approach can be considered as suitable for the given project objectives i.e. the assessment of the hydrological dynamics of the Latyan catchment. Hereby, the model can be used to elaborate important hydrological information for a sustainable management of the water resources.