In order to create hydraulic models which enable credible simulation of flood water, up-to date information are of high importance. Namely, the data used for hydraulic models is often outdated and does not describe actual state on the field. In fact, the hydraulic conductivity of the streams is strongly influenced by the geometry of the channel and the roughness characteristics of the stream channel, which are variable factors that are all time dependent.
In this master thesis problems and an overview of current maintenance work in Ljubljanica river at the Špica section are presented. New hydraulic model based on detailed bathymetry measurements of Ljubljanica river bottom, measured flow data and hydraulic conditions in the channel was made for this section. Old cross sections geometry data of Ljubljanica river channel were also included in a seperated model geometry. The results of hydraulic calculations using different geometric data were compared to each other. The reason for changes in geometry of the channel at the Špica junction lies in sediment depositing between outflow of Mali graben river and Špica junction, and at the location where main Ljubljanica river splits to the Gruber channel and Mestna Ljubljanica channel. We also prepared suggestions for improvement of the hydraulic conductivity of Ljubljanica river on this section.