The article investigates the dependence of the output parameters of a new device of a micro hydroelectric power station with a hydro-turbine operating on the basis of the reactive principle on the factors of water flow and design. It has been experimentally confirmed that the necessary calculations for a new design can be performed using a kind of differential equations for jet propulsion. It has been determined that the operational parameters obtained by experimental testing of the manufactured device of a micro hydroelectric power station differ from the calculation results by only 4 ÷ 5%.