Run-off-river hydro projects can create sustainable energy minimizing impacts to the surrounding environment. Among many advantages of these systems, whose development has in fact been largely supported during the past years by the confederation, their main limitation is that their functioning is dependent by the available discharge, as they do not have storage. In order to overcome this constrain and enhance their flexible use, the Smart Storage Operations (SSO) are introduced (Figure 1c). SSO consist on using temporarily some existed underground structures of the power plant, such as the settling basin, for water storage. This water can be used afterward to produce peak energy timed with the demand. This is particularly useful since it allows water accumulation in periods of the year when the discharge is too low for energy production, therefore minimizing water losses. The aim of this study was to create a hydrological-hydraulic model in order to reproduce the HPP operations (both under normal use - Figure 1b - and SSO - Figure 1d). The elaborated framework was applied at the hydropower plant KW Gletsch-Oberwald (Figure 1a) located at Valais (Switzerland) but it can be applied to others HPP in the Alpine region with dominant glacier cover, or areas with an intermittent river. A validation of the model was possible thanks to the measurements which were collected at the HPP during one week of site tests.