Fluvial transport, its dynamics and structure, constitute a good indicator of the condition of the natural environment in various climatic zones. Analysis of fluvial transport components allows for precise determination of the rate and directions of transformations of geosystems of any importance. In the polar zone, very sensitive to global changes, it seems expedient to identify the mechanisms and structure of fluvial transport, particularly in the conditions of the observed glacier retreat, the main alimentation source of proglacial rivers. Studies carried out in the zone revealed difficulties in determination of fluvial transport structure, particularly the actual bedload of gravel-bed rivers based on direct measurements, resulting from: short measurement series, lack of standardization of research methods and measurement equipment, and strategy of selection of study objects and sampling. The research project presented concerns determination of mechanisms of fluvial transport and sediment supply to Arctic gravel-bed river channels. The mechanisms reflect the processes of adaptation of proglacial rivers of the Arctic zone to changing environmental conditions, and indicate the dominant directions of transformations of paraglacial geosystems of various importance. For studies on Arctic geosystems, the region of the south Bellsund (SW Spitsbergen) was selected due to extensive knowledge on its hydro-meteorological and glacial-geomorphological conditions, and long-term measurement series carried out by the research station of the MCSU, among others within the framework of the international monitoring network: SEDIBUD (IAG) and Small-CATCHMENT program. For detailed studies, rivers with various hydrological regimes were selected, functioning at the forefield of the Scott and Renard Glaciers. The Scott River glacial catchment and glacier-free catchments of the Reindeer Stream and the Wydrzyca Stream (with a snow-permafrost hydrological regime) meet the selection criteria for representative test catchments analyzed for the following programs: SEDIFLUX, SEDIBUD, and POP.