5. Conclusions
Hydrologic interaction can be defined in a way that represents the physical characteristics of a watershed as realistically as possible and can be applied to regional management. Remote sensing data with a revised version of the SWAT+ model were used to study surface water processes such as river discharge and sediment yield variation. This hydrological model enabled spatial visualization of dynamics and changes in the distributions of inorganic nutrients and TSS. Spatial modeling of the distribution of inorganic nutrients is useful for calculating their continuous concentrations in tributaries and the main stream. In both catchment areas, the spatial regression analysis was utilized to identify those areas that were prone to inorganic nutrient loss. There was no effect of the land use in the catchment area on the concentration of TSS in the watercourses. However, the cross-sectional turbulence coefficient results in higher TSS and inorganic nutrient fluxes in the main streams. Moreover, the watershed areas tend to accumulate TSS in their different subcatchments, which implies that it is less susceptible to leaching. In future studies, other forms of nutrients (e.g., organic compounds) or pollutants should be considered on a larger scale.