The scope of the thesis is to present the possibility of building a small hydropower plant on the Gacka River in Lika-Senj County. The area belongs to an ecologically significant area, therefore it is subject to special regulations that must be followed. The flow of the river and the available net head were analyzed, the location of the planned hydropower plant was selected and a technical solution was developed. A statistical analysis was made from the collected flow data of a multi-year period and a comparison of the flow duration curve was made according to two methods, Gaussian and Log Pearson III distribution, which was chosen as the authoritative one. Based on the installed flow, the type of turbine and the power of the generator were selected, the investment costs of the hydropower plant, sales revenues were calculated, the investment payback period, i.e. the economic justification of the construction, was presented, and at the end of the work, a schematic representation of the turbine and powerhouse and the floor plan of the small hydropower plant was given.