Understanding and knowledge about the processes that define water or hydrologic cycle and
erosion-sedimentation cycle (these two cycles are inter-connected) is important in order to ensure
safety during natural disasters and to provide suffcient conditions for life (e.g. drinkable
water). In the presented thesis we investigated next processes:
uvial transport of suspended
sediments, surface runoff, rainfall and erosion processes.
Firstly, the investigated hydrological processes are described, then the measuring methods
are presented. Further, the investigated catchments including experimental catchment where
high-frequency measurements were performed are described, in the next section the statisticalmathematical
tools that were used for data analysis are shown. The emphasis was given to
the copula functions that can be used for simultaneous study of two or more (in)dependent
variables that define the environmental process. In the last section of the first part of thesis,
the basic concepts of soil erosion modelling are presented where the emphasis was given to the
WATEM/SEDEM model that can be used for soil erosion modelling.
In the second part of the thesis, results of field measurements are presented (e.g. measurements
of
uvial transport of suspended sediments, rainfall, discharge and soil erosion), analysis of connection
between
uvial transport of suspended sediments and other hydrological processes was
carried out, soil erosion modelling results are described and application of copula functions is
shown on practical examples.
The main conclusions are: rainfall events that have large rainfall intensities have significant impact
on erosion, transport and deposition processes. During these kinds of events the suspended
sediment budgets can be for a few orders of magnitude larger than the long-term annual rates. In
Slovenia the peak of the suspended sediment transport mostly occurs before the peak discharge
but the time differences are rather small (up to 1 day). Moreover, the trends in the transport of
suspended sediments in Slovenian streams are mostly negative (all statistically significant trends
are negative). Reasons for this can be: closing of mines or foresterisation (abandoning of farming
due to urbanisation). Application of the WATEM/SEDEM model showed that sediment delivery
ratio decreases with increasing catchment area. Moreover, copula functions were used for
multivariate
ood frequency analysis where peak discharge, hydrograph volume and hydrograph
duration were considered in the analysis. Moreover, copula functions were also used to analyse
suspended sediment data and for the estimation of the suspended sediment values based on the
measured discharge and rainfall values.
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