D. Prodanović, M. Stanić, N. Milivojević, Z. Simić, B. Stojanović
The particularity of “Vlasina” hydropower plants catchment is a big number of gravitation
channels used to collect the water from neighboring natural catchments. The overall catchment
size is thus increased, compared to the natural catchment. At the bifurcations where the
gravitation channels with mild slope are intersecting the steep natural hydrographic network, the
natural surface and subsurface water flows are significantly altered. The channel which
intersects the river flow will hold the water at higher elevations, filling the storages or
transferring the water to another catchment. Under such conditions, the concept of rainfall to
runoff transformation in SWAT-based model had to be modified in a way that the channel does
not capture all the water from the natural watercourse, but will allow a certain volume of water
to run downstream, both for the surface and subsurface flow. New SWAT-related objects were
introduced: HPN (hydro-profile on the natural watercourse), HPC (hydro-profile on the
channel), HPI (hydro-profile on the channel, the intake) and HPS (storage hydro-profile). For
each object the water balance and transformation equations were derived, adapting SWAT
model to simulate the flow in the bifurcating network of natural streams and channels. The new
model was calibrated on the catchment area of the “Vlasina” hydropower plants system. This
paper presents the adaptations of the SWAT-based model and results of its application on the
northern part of the system (catchments of the channels “Strvna” and “Čemernik”).