## 3 Using the Digital Platform--DNS/SWAT  
In order to track suspended sediment transport in the land and riverbed phase of the pilot basin, the most important SWAT module was used on the digital platform--DNS, which was supported by data processing (LOAD ESTimator), and database modules (meteorological and land use). The use of the United States Geological Survey (USGS) FORTRAN--LOAD ESTimator program [123] made it possible to take into account the sediment concentration in, i.e., extreme flow situations, using the available interpolated sediment observations to fill the time gaps. LOADEST provides an estimate of the sediment load as a function of the observed daily river flow. This function is determined by performing a linear regression analysis between the available sediment concentration observations and the corresponding river flow data. In turn, the database module (meteorological and land use) made it possible to take into account the data on the current and future average monthly temperatures, and precipitation [124], as well as the results of the FORECOM project for the entire area of the Polish part of the Western Carpathians [125], taking into account the forecast changes in land use. This allowed for the creation of variant scenarios and the study of the effects of changing one, or several parameters over time. The Raba basin area, which is over 131 km long, is part of the Polish Western Carpathians. Its sources are located in the Gorce mountain range at an altitude of 780 m a.s.l., and the estuary to the Vistula River at a height of 180 m a.s.l. [126; 127]. The choice of this basin for research with the use of the digital platform--DNS/SWAT was related, i.e., by its dual nature and location (Figure 2). The mountainous nature of its upper part manifests itself in a quick reaction to rainfall and high dynamics of surface runoff. On the other hand, in the lower part, as the height of the slopes decrease, the amount of precipitation and the dynamics of surface runoff also decrease [128]. It is also an area dominated by agriculture, which further contributes to soil loss in the area. The Raba riverbed phase is complex. The main bed runs through the bottom of an alluvial valley and is characterized by a relatively steep slope, a significant inflow of sediments from the slopes, and frequent floods [128; 129; 130]. Moreover, features of the basin area, such as its location in an area particularly exposed to water erosion, the proximity to one of the largest Polish urban agglomerations--Krakow, and the presence of a dam reservoir halfway along the river, make both quantitative and qualitative tracking of sediments a challenge. The land use (CLC, 20 m resolution), soil types (1:5000, IUNG, 2.5 m resolution), and slopes, made it possible to divide the analyzed area into a total of 902 HRU. for which the calculations were performed. Then they were aggregated to a level of 36 sub-basins (Figure 2) with an average area of 4214 ha, determined on the basis of DEM (1:20,000, IMWM-PIB), and maps of hydrographic divisions (1:10,000, IMWM-PIB). Meteorological conditions were represented in the model, on the basis of data, on precipitation, temperature, solar radiation, humidity, and wind directions from 1992-2016 from 75 meteorological stations (IMGW-PIB). Access to the data of the Dobczye dam reservoir (area, volume, maximum and minimum daily runoff, water damming height, as well as concentration and diameter of sediment particles in the reservoir) came from field studies. The model calibration (Myslenice and Proszowki) and validation process (Stradomka) and the preceding sensitivity analysis were carried out using the SWAT-CUP program [131], and the SUFI-2 algorithm [39; 132]. The SUFI-2 algorithm tries to capture as many optimal simulations as possible that are within the 95% prediction certainty. The algorithm does not obtain a unique value for the parameters, but an interval that includes all the uncertainties of the processes in the basin.