Vízügyi Közlemények, 2004 (86. évfolyam)

3-4. füzet - Rövidebb tanulmányok, közlemények, beszámolók

606 Szilágyi József Szigyártó Z.: Gyakorlati módszerek a nempermanens viszonyok közötti vízhozam meghatározására: 2. Vízhozam meghatározás a vízállás változás intenzitása alapján. Hidrológiai Közlöny, 3: 1985. Szilágyi, J.: State-space discretization of the Kalinin-Milyukov-Nash cascade in a sample-data system framework for streamflow forecasting. Journal of Hydrologie Engineering, 8(6). 2003. Szöllősi-Nagy A.: The discretization of the continuous linear cascade by means of state-space analysis. Journal of Hydrology, 58. 1982. He * * Increasing the accuracy of river water level forecasting by applying the Jones formula by József SZILAGYI hydrologist Forecasting of the water level of rivers can be made more accurate when the Jones formula is applied to the steady state flow rating curves. In the theoretical example of the paper the forecasting of the water level of the downstream station was first made with the steady-state flow rating curve (Figure 1) then it was repeated by using the Jones formula for transforming the water levels into discharge values (Figure 2) and back, applying a hydrological model. This way a 30% increase of the accuracy was obtained during the flow routing as compared to the solution generated by numerically integrating the SaintVenant equations, as the reference value. The experiences with a practical case, the Danube section between Budapest and Paks, yielded more moderate results; a 15% improvement in the mean least-square error for the model year 2002 (Figures 3-4). These experiences demonstrated the practical usefulness of the Jones formula in improving water level forecasts and modelling. With the help of the Jones formula realistic looped flow-rating curves were generated (Figure 5) for the lower as well as for the upper boundary station of the river reach modelled.