The conducted research solves the risk calculation problem of water overtopping theroad in the culvert cross-section on the ephemeral stream by applying the probabilisticrisk assessment model and the hydrological-hydraulic model of the analyzedphenomenon. The new hydrological-hydraulic model of risk assessment, whichincludes several new process-modeling approaches to the analyzed phenomenon,represents one of the contributions of the research. The new risk assessment model hasbeen applied to the 67 concrete road culverts at the experimental road section of theRaΕ‘ka – Novi Pazar road in the Republic of Serbia. By applying the model to theculverts of the experimental road section, it was determined that the stone sedimentfilling of road culverts is the main cause of high-risk values. Within the new riskassessment model, an impact analysis of the rehabilitation and reconstruction worksapplication in order to reduce the risk value has been performed. The results of allconducted analyzes are shaped in the technical report form of the risk assessment ofthe analyzed phenomenon and represent the model output. The obtained results havebeen discussed concerning the results of similar research in the world, based on whichconclusions have been made and further research directions in the studied field havebeen given.Β