Vízügyi Közlemények, 1999 (81. évfolyam)

2. füzet - Zellei L.-Sziebert J.-Csonki I.-Kaszab G.: A Sió vízszállító képessége

A Sió vízszállító képessége 273 releases of 1996 and the flow domain of 69-71 m

3/s measured in the spring of 1997 indicated, that this latter range is about the maximum flow carrying capacity of the canal. The hydraulic capacity of stream channels can be best surveyed by carrying out a series of water level and discharge measurements and determining the flow-rating curves. In the 120 km long Canal Sió (Fig. I.) the only station with reliable flow-rating curve is the Simontornya station. Variation of the flow carrying capacity in the growing season (Figs. 4. and J.) and the changes of the channel cannot be followed by discharge measurements due to the high time requirements, thus they can not aid the planning of operation and maintenance activities. It is similarly difficult to estimate the water surface profile between two water level gauges, which are far from each other. The computer model (Fig. 1.) used for the calculation was based on the one-dimensional quasisteady state flow equation of stream channels. The data base consisted of the data of the channel geometry and roughness, varying from reach to reach and also within the cross-section. Changes of the channel of the Canal Sió were considered on the basis of channel surveys of varying reliability and also by the data of the original design, where measurement data were missing (Fig. 2.). The model was run with discharge data measured between March and November, 1988, at several occasions (Fig. J.). During the November flow release from the lake the water surface slope was also measured. Segmentation of the model calculation was made on the basis of the variation of the channel roughness. The calculated Manning coefficients (Table I.) were in no detectable relation neither with the channel-reaches nor with the water depths. Consequently the roughness was considered with three Manning values («=0.035, 0.040 and 0.045 s m1'

3) over the whole river reach, for the three calibration discharges (0=32, 44 and 56 m

3/'s) (Fig. 6.). Discharge values calculated with the above three channel-roughness coefficients were compared to the respective values of the rating curves of the Siójut gauge (Fig. 7.), the Simontornya gauge (Fig. 8.) and the Pálfa gauge (Fig. 9.). These figures indicate that acceptable fit was achieved in certain discharge domain only. Roughness coefficients giving the best fit, changing from canal section to canal section, were used for the computation. The flow carrying capacity of the Canal Sió was simulated in two alternatives. Upstream boundary conditions were the following release flows of the Siófok gate: ö|=32, Q

2=40, £?з

=50, 04

=6O, 05=70 and <2

6=80 m Vs. The alternatives investigated differ from each other in'the discharge of the two main tributaries of the Sió (the rivers Kis-Koppány and Kapos). Variation of the channel roughness was as shown in Fig. 10. In alternative 1. the gradually changing steady state flows, induced by the release flow of the Siófok gate, was considered. The tributaries Kis-Koppány and Kapos were considered with the flows Q=

2 m/s and Q= 10 m

3/s, respectively (Fig. 11.). In alternative 2. also the gradually changing steady state flows of the Siófok gate were considered but with the 0=10 nvVs and 0=30 m'/s flows of the tributaries Kis-Koppány and Kapos, respectively (Fig. 12.). The surface profile curves generated for the various flow domains provide an effective decision support tool for the regulation of the water levels of Lake Balaton and for the regulation and flood control of the Canal Sió. * * * Die Wasserführungsfähigkeit des Sió-Kanals von Dipl.-Ing. László ZELLEI. Dipl.-Ing. János SZ1EBERT, Dr.-Ing. István CSONKI und Dipl.-Ing. Gábor KASZAB Die Verschlechterung der wirtschaftlichen Bedingungen für die Wasserwirtschaft sowie die Zunahme der mit den in die Naturprozesse vorgenommenen Eingriffen verbundenen Aufmarksamkeit und Empfindlichkeit erfordern eine Erhöhung des Niveaus der Methoden und Verfahren der Gewäs-