## 1 Introduction
Despite these difficulties, attempts have been made to make such connections. They often relate to extending the potential of models such as SWAT (Soil and Water Assessment Tool) [37; 38; 39], which is one of the highest rated tools in terms of water-quality modeling on the basin scale [21]. Until now, SWAT has been combined with models such as UCA2D-SCILA [40], EFDC [41], SOBEK [42], CLUE-S model [43] or HSPF [44], and methods such as remote sensing and image analysis--OBIA [45] or fingerprinting [30; 46]. The combination and use of the best features of the available tools, grouped in one digital space, therefore seems to be an opportunity especially for mountainous areas, which are more difficult to model and particularly vulnerable to soil loss, such as the Western Carpathians. This area is one of the important soil erosion \"hot spots\" in Europe [47; 48; 49; 50], and covers the area of Slovakia and Poland, as well as parts of the Czech Republic, Hungary, and Austria. The Western Carpathians were characterized by dynamic changes which today have a significant impact on both the land and the riverbed phases of this area. A strong drive to use the riverside land in agriculture and to protect the valleys against floods meant that from the second half of the 20 th century, extensive regulatory work was carried out in the Polish part of the Western Carpathians, which consequently led the river to become much narrower, simpler, and shorter [51]. The result of this man-made process was a significant increase in riverbed erosion [52; 53; 54]. Moreover, the transformation of the centrally planned economy into a free market economy, which took place in 1989, resulted in a decrease in the profitability of agricultural production and its successive replacement with forested areas, thus limiting water erosion and surface runoff in the land phase [48; 55]. For several years, attempts have been made to track the sediment transport in this area in both phases of the river basins. Erosion and sediment yield analyses focused on the use of both the digital elevation model (DEM) [56], commonly known empirical models (e.g., Universal Soil Loss Equation--USLE and its modifications MUSLE and RUSLE) [57; 52], and more advanced environmental models, such as SWAT [58; 59]. It is much more difficult to find examples of the use of models to simulate sediment transport in the riverbed phase. Earlier analyses of sediment transport in this area for this phase were mainly based on the results of in situ research [19; 60; 61; 62]. The aim of this article is to present the current state of knowledge in the field of interdisciplinary studies of sediment transport in the basin area, with a particular emphasis on the mountain areas of the Western Carpathians. The manuscript presents the possibilities of using the developed digital platform--DNS (Discharge-Nutrient-Sea) with a SWAT module, to track soil particles from the source to the deposition in the pilot basin of the Raba River located in the Polish part of the Western Carpathians. This basin, due to its dual character and presence of a dammed reservoir, highlighted both the strengths and weaknesses of SWAT. This allowed to evaluate the possibilities and effectiveness of combining models, methods, and databases as further modules of the digital platform, expanding the possibilities and reducing limitations in tracing sediments both in the land and riverbed phase.