The Gradna stream is located on the slopes of the Samobor mountains and consists of two main tributary streams, the Lipovečka Gradna and the Rudarska Gradna, which merge upstream of the city of Samobor. The main characteristics of streams in the Gradna basin are flash floods, so it was necessary to build a range of hydrotechnical buildings to prevent road and settlement flooding in the Samobor area. The main goal of this thesis is to research the effects hydrotechnical buildings have on the hydromorphology of the stream, river channel, banks/riparian zone and floodplain. It will determinate the hydromorphological characteristics of the Gradna stream by analyzing available references, conducting a field research, and by following the guidance of Water Framework Directive all with the help of the document Guideline for Hydromorphological Monitoring and Assessment of Rivers in Croatia. The result of this research is a moderately modified hydromorphological status of the whole stream. This result is affected by numerous stream regulations because of the flash floods that are common in this area.