AbstractFlood protection is at present very actual topic and it has come to the forefront due to the increased incidence of climatic and hydrological extremes, and the related increased incidence of flood events. Flood protection objects – construction projects are a trend in flood protection and prevention in developed countries around the world. In their preparation, implementation, evaluation and authorization it is necessary to ensure consistent application of the environmental impact assessment in accordance with Law No. 24/2006 Coll. on Environmental Impact Assessment, as amended in the Slovak Republic, so as to ensure the validity of the assessment. What is important is the selection of environmentally acceptable alternative solutions. The proposed risk index calculation is based on multicriteria method. The proposed assessment may be used in the process of comparing alternatives and the choice of optimum alternative for the purposes of environmental impact assessment of hydraulic structures. Application of the calculations for Večný stream in the village of Malcov proved that Alternative 0, Alternative 1 and Alternative 2 have different levels of risk acceptability and achieve different risk index values. Based on the risk index the suggested alternatives can be compared with each other, evaluated by multicriteria method and thus we recommend the construction of Alternative 1, which represents the lowest risk to the environment.