In-Situ Measuring Campaign at the Hydropower Plant ‘‘Perućica’’, Montenegro - Part 1: Open Channel System - Page 10

Figures 24-26 show unsteady flow with a lowering of water levels, caused by the difference between the upstream and downstream discharge. The downstream discharge is actually the discharge of the HPP.

The compensation basin, as mentioned earlier, due to its volume, reduces the gradient of the water level trend. At the same time, there are discharge oscillations between the compensation basin and the canal. Consequently, water levels in the compensation basin and the canal oscillate as well. According to Figures 24-26, the oscillation period is about 3 minutes. The oscillations are more regular in the compensation basin, than in the canal.



Figure 24: Water level in the Zeta 1 Canal (upstream of the Compensation Basin) on 24 June 2010



Figure 25: Compensation Basin (Water Level) on 24 June 2010



Figure 26: Water level at the Power Intake before the Trash Rack on 24 June 2010


These measurements provided the relevant unsteady flow data for large discharges, needed for the calibration of the mathematical model.

The discharge measuring during the presented two groups of measurements was aimed at providing the values of boundary conditions for mathematical modeling, but also to determine the hydraulic characteristics of the gates and rating curves.

In Figure 27, the existing rating curve (provided by the National Hydrological Service) is presented together with the current measurement results. It could be observed that for the low discharges, the agreement is relatively good, but there are significant differences for the higher discharges. Bearing in mind the importance of this information, it is clear that measurements aimed at improving the rating curve should be done.



Figure 27: Existing Rating Curve vs. Measurement Results