Rainfall-Runoff Modeling of the Nested Non-Homogeneous Sava River Sub-Catchments in Slovenia

Abstract

Rainfall-runoff modeling is nowadays applied for water resources management, water system design, real-time forecasting, flood design and can be carried out by using different types of hydrological models. In this study, we focused on lumped conceptual hydrological models and their performance in diverse sub-catchments of the Sava River in Slovenia, related to their size and non-homogeneity. We evaluated the difference between modeled and measured discharges of selected discharge gauging stations, using different model performance criteria that are usually applied in hydrology, connecting the results to geospatial analysis of geological and hydrogeological characteristics, land use, runoff potential, proportion of agglomeration and various meteorological variables. Better model performance was obtained for catchments with a higher runoff potential and with less variations in meteorological variables. Regarding the number of used parameters, the results indicated that the tested Genie Rural 6-parameter Journalier (GR6J) model with 6 parameters performed better than the Genie Rural 4-parameter Journalier (GR4J) model with 4 parameters, especially in the case of larger sub-catchments. These results illustrate the comprehensive nature of lumped models. Thus, they yield good performance in case of the catchments with indistinguishable characteristics.