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.