The primary aim of this research was to investigate and to substantiate available methodologies based on key hydrologic, hydraulic and geometric parameters of a river to derive the theoretical hydrokinetic (HK) power. To realize this aim, hydrological and hydraulic methods were applied for the second largest river in the country. For the hydrological evaluation of the hydrokinetic resource historic, standard, stream gauging stations records (river stage, flow and velocity–area) analyzed. The one-dimensional hydraulic model HEC-RAS 4.1 was used with the GIS extension GeoRAS to perform river hydraulic calculations. A high-resolution digital elevation model of the streambed was employed. The model calibration to adjust Manning׳s coefficient was performed after the stream surface slope and discharge were measured.
Once the model was calibrated, the simulations of the mean annual, bankfull and low flows were used to identify the key hydraulic and geometric variables at the cross sections: the mean velocity, the flow geometry (the width, the mean depth, and the cross sectional area), and the specific stream power. The modeled parameters were compared to the independent dataset resulting from the stream gauging stations records. The validation indicates that the hydraulic geometry can be modeled satisfactorily at the selected river cross-sections. Based on this data, the theoretical hydrokinetic power and the power density along the river (100 cross-sections spacing) were determined. To assess the technically recoverable hydrokinetic resource will require assumptions regarding the energy extraction by installed turbines, the acceptable spacing between the installed turbines along and across the river, and the natural environmental conditions.